Groups And Periods On The Periodic Table

How many periods and groups are on the periodic table?

There are 18 vertical columns or groups and 7 horizontal rows or periods in the modern periodic table.

How do you find the period of an element?

How to Find the Period of an Element? – The value of n for the outermost or valence shell is shown by the period. The number of shells in an atom determines the period. The period of an element is represented by the principal quantum number (n) of the valence electrons in the electronic configuration of an atom.

The number of shells equals the number of periods when determining a period. Example: Na- 2,8,1 – There are three shells, hence the period number is 3. Calcium – 2,8,8,2 – There are four shells, hence period number is four.

Are there 8 or 18 groups?

The s-, p-, and d-block elements of the periodic table are arranged into 18 numbered columns, or groups.

What is the difference between a group and a period?

The Difference Between an Element Group and Period Groups and periods are two ways of categorizing elements in the periodic table. Periods are horizontal rows (across) the periodic table, while groups are vertical columns (down) the table. Atomic number increases as you move down a group or across a period.

IUPAC Name Common Name Family Old IUPAC CAS notes
Group 1 alkali metals lithium family IA IA excluding hydrogen
Group 2 alkaline earth metals beryllium family IIA IIA
Group 3 scandium family IIIA IIIB
Group 4 titanium family IVA IVB
Group 5 vanadium family VA VB
Group 6 chromium family VIA VIB
Group 7 manganese family VIIA VIIB
Group 8 iron family VIII VIIIB
Group 9 cobalt family VIII VIIIB
Group 10 nickel family VIII VIIIB
Group 11 coinage metals copper family IB IB
Group 12 volatile metals zinc family IIB IIB
Group 13 icoasagens boron family IIIB IIIA
Group 14 tetrels, crystallogens carbon family IVB IVA tetrels from the Greek tetra for four
Group 15 pentels, pnictogens nitrogen family VB VA pentels from the Greek penta for five
Group 16 chalcogens oxygen family VIB VIA
Group 17 halogens fluorine family VIIB VIIA
Group 18 noble gases, aerogens helium family or neon family Group 0 VIIIA

Another way to group elements is based on their shared properties (in some cases, these groupings do not correspond to the columns in the periodic table). Such groups include, alkaline earth metals, transition metals (including rare earth elements or lanthanides and also actinides), basic metals, metalloids or semimetals, nonmetals, halogens, and noble gases.

Within this classification system, hydrogen is a nonmetal. The nonmetals, halogens, and noble gases are all types of nonmetallic elements. The metalloids have intermediate properties. All of the other elements are metallic. Elements in a period share the highest unexcited electron energy level. There are more elements in some periods than others because the number of elements is determined by the number of electrons allowed in each energy sub-level.

There are seven periods for :

Period 1: H, He (does not follow the octet rule)Period 2: Li, Be, B, C, N, O, F, Ne (involves s and p orbitals)Period 3: Na, Mg, Al, Si, P, S, Cl, Ar (all have at least 1 stable isotope)Period 4: K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Kr (first period with d-block elements)Period 5: Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sn, Te, I, Xe (same number of elements as period 4, same general structure, and includes first exclusively radioactive element, Tc)Period 6: Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, At, Rn (first period with f-block elements)Period 7: Fr, Ra, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Rd, Db, Sg, Bh, Hs, Mt, Ds, Rg, Cn, Uut, Fl, Uup, Lv, Uus, Uuo (all elements are radioactive; contains heaviest natural elements)

: The Difference Between an Element Group and Period

What is a group of 14 called?

Another name for Group 14 is the Carbon family. The outermost shell electronic configuration of 14- Group elements is ns 2 np 2. This indicates their tetravalent nature in an excited state.

Are there 18 groups and 7 periods in the periodic table?

The given statement is absolutely correct. there are 7 periods and 18 groups in the modern periodic table.

What are the group numbers?

The periodic table has eight main groups: 1, 2, 13, 14, 15, 16, 17, and 18 ( Ia, IIa, IIIa, IVa, Va, VIa, VIIa, and 0, respectively ). The group number represent the valence electron (s) present in the elements belonging to a specific group.

What is a group in chemistry?

group, in chemistry, a column in the periodic table of the chemical elements, In a group, the chemical elements have atoms with identical valence electron counts and identical valence vacancy counts. This similarity in both the composition and structure of their atomic valence shells implies a corresponding similarity in both their chemical and physical properties.

Groups are numbered from 1 to 18. From left to right in the periodic table, there are two groups (1 and 2) of elements in the s -block, or hydrogen block, of the periodic table; ten groups (3 through 12) in the d -block, or transition block; and six groups (13 through 18) in the p -block, or main block.

The elements in the f -block, or inner-transition block, the lanthanoids and actinoids, are not given group numbers. The Editors of Encyclopaedia Britannica This article was most recently revised and updated by Erik Gregersen,

What is the unit of period?

The nature of a wave was discussed in Lesson 1 of this unit. In that lesson, it was mentioned that a wave is created in a slinky by the periodic and repeating vibration of the first coil of the slinky. This vibration creates a disturbance that moves through the slinky and transports energy from the first coil to the last coil.

  • A single back-and-forth vibration of the first coil of a slinky introduces a pulse into the slinky.
  • But the act of continually vibrating the first coil with a back-and-forth motion in periodic fashion introduces a wave into the slinky.
  • Suppose that a hand holding the first coil of a slinky is moved back-and-forth two complete cycles in one second.
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The rate of the hand’s motion would be 2 cycles/second. The first coil, being attached to the hand, in turn would vibrate at a rate of 2 cycles/second. The second coil, being attached to the first coil, would vibrate at a rate of 2 cycles/second. The third coil, being attached to the second coil, would vibrate at a rate of 2 cycles/second. In fact, every coil of the slinky would vibrate at this rate of 2 cycles/second. This rate of 2 cycles/second is referred to as the frequency of the wave.

  1. The frequency of a wave refers to how often the particles of the medium vibrate when a wave passes through the medium.
  2. Frequency is a part of our common, everyday language.
  3. For example, it is not uncommon to hear a question like “How frequently do you mow the lawn during the summer months?” Of course the question is an inquiry about how often the lawn is mowed and the answer is usually given in the form of “1 time per week.” In mathematical terms, the frequency is the number of complete vibrational cycles of a medium per a given amount of time.

Given this definition, it is reasonable that the quantity frequency would have units of cycles/second, waves/second, vibrations/second, or something/second. Another unit for frequency is the Hertz (abbreviated Hz) where 1 Hz is equivalent to 1 cycle/second.

If a coil of slinky makes 2 vibrational cycles in one second, then the frequency is 2 Hz. If a coil of slinky makes 3 vibrational cycles in one second, then the frequency is 3 Hz. And if a coil makes 8 vibrational cycles in 4 seconds, then the frequency is 2 Hz (8 cycles/4 s = 2 cycles/s). The quantity frequency is often confused with the quantity period.

Period refers to the time that it takes to do something. When an event occurs repeatedly, then we say that the event is periodic and refer to the time for the event to repeat itself as the period. The period of a wave is the time for a particle on a medium to make one complete vibrational cycle.

  1. Period, being a time, is measured in units of time such as seconds, hours, days or years.
  2. The period of orbit for the Earth around the Sun is approximately 365 days; it takes 365 days for the Earth to complete a cycle.
  3. The period of a typical class at a high school might be 55 minutes; every 55 minutes a class cycle begins (50 minutes for class and 5 minutes for passing time means that a class begins every 55 minutes).

The period for the minute hand on a clock is 3600 seconds (60 minutes); it takes the minute hand 3600 seconds to complete one cycle around the clock. Frequency and period are distinctly different, yet related, quantities. Frequency refers to how often something happens.

  1. Period refers to the time it takes something to happen.
  2. Frequency is a rate quantity.
  3. Period is a time quantity.
  4. Frequency is the cycles/second.
  5. Period is the seconds/cycle.
  6. As an example of the distinction and the relatedness of frequency and period, consider a woodpecker that drums upon a tree at a periodic rate.

If the woodpecker drums upon a tree 2 times in one second, then the frequency is 2 Hz. Each drum must endure for one-half a second, so the period is 0.5 s. If the woodpecker drums upon a tree 4 times in one second, then the frequency is 4 Hz; each drum must endure for one-fourth a second, so the period is 0.25 s. Since the symbol f is used for frequency and the symbol T is used for period, these equations are also expressed as: The quantity frequency is also confused with the quantity speed. The speed of an object refers to how fast an object is moving and is usually expressed as the distance traveled per time of travel. For a wave, the speed is the distance traveled by a given point on the wave (such as a crest) in a given period of time.

So while wave frequency refers to the number of cycles occurring per second, wave speed refers to the meters traveled per second. A wave can vibrate back and forth very frequently, yet have a small speed; and a wave can vibrate back and forth with a low frequency, yet have a high speed. Frequency and speed are distinctly different quantities.

Wave speed will be discussed in more detail later in this lesson,

What is the period of sin?

The period of the sine curve is the length of one cycle of the curve. The natural period of the sine curve is 2π.

What is the period in a number?

Place Value When a whole number is written using the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9, it is said to be in standard form, The position of each digit determines the digit’s place value, A place value chart names each place value. When a number is written in standard form, each group of digits separated by a comma is called a period, To write a whole number in standard form, write the number named in each period, and replace each period name with a comma.5,913,603,800 is read “five billion, nine hundred thirteen million, six hundred three thousand, eight hundred.” Practice 1. Write 35,582,075 in words.2.

What does group number tell you?

The periodic table in terms of electronic structure – The group number of an element tells you how many electrons there are in the outer shell and the period number tells you how many electron-containing energy shells the element has. All elements in the same group have the same number of electrons in their outer energy shell.

Does Group 8 exist?


primordial element
synthetic element
Atomic number color:


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Group 8 is a group (column) of chemical elements in the periodic table, It consists of iron (Fe), ruthenium (Ru), osmium (Os) and hassium (Hs). “Group 8” is the modern standard designation for this group, adopted by the IUPAC in 1990. It should not be confused with “group VIIIA” in the CAS system, which is group 18 (current IUPAC), the noble gases,

In the older group naming systems, this group was combined with groups 9 and 10 and called group “VIIIB” in the Chemical Abstracts Service (CAS) “U.S. system”, or “VIII” in the old IUPAC (pre-1990) “European system” (and in Mendeleev ‘s original table). The elements in this group are all transition metals that lie in the d-block of the periodic table.

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While groups (columns) of the periodic table are sometimes named after their lighter member (as in “the oxygen group” for group 16), the term iron group does not mean “group 8”. Most often, it means a set of adjacent elements on period (row) 4 of the table that includes iron, such as chromium, manganese, iron, cobalt, and nickel, or only the last three, or some other set, depending on the context.

What are group 0 elements called?

The elements in group 0 are called the noble gases. They exist as single atoms.

What is Group 8 called?

The Parts of the Periodic Table Group 8A (or VIIIA ) of the periodic table are the noble gases or inert gases : helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). The name comes from the fact that these elements are virtually unreactive towards other elements or compounds.

They are found in trace amounts in the atmosphere (in fact, 1% of the atmosphere is argon); helium is also found in natural gas deposits. In their elemental form at room temperature, the Group 8A elements are all colorless, odorless, monatomic gases. The Group 8A elements have a full octet of eight valence electrons in their highest-energy orbitals ( ns 2 np 6 ), so these elements have very little tendency to gain or lose electrons to form ions, or share electrons with other elements in covalent bonds.

They can be forced to form compounds with other elements, but require special conditions to do so. Xenon, krypton compounds are known (this was first accomplished by Neil Bartlett in 1962), including XeF 2, XeF 4, XeF 6, XeOF 2, XeOF 4, XeO 2 F 2, XeO 3 F 2, XeO 2 F 4, XeO 3, XeO 4, KrF 2, RnF 2, among others.

(He, Z=2). Helium is a colorless, odorless, unreactive gas which liquefies at -268.97 ° C (4.18 K). The name “helium” is derived from the Greek word for the Sun, helios, Helium was originally discovered on the Sun in 1868 by Pierre Janssen: his analysis of the light emitted from the Sun’s corona during a solar eclipse showed that there were lines in the Sun’s spectrum that were produced by a previously unknown element.

When helium was found on Earth in the late 1890’s (in association with uranium ores), it was found to have the same emission spectrum as the element previously found in the Sun, indicating that it was indeed the same element. The concentration of helium in the Earth’s crust is about 8 ppb, making it the 71st most abundant element; it is found in the atmosphere at a concentration of 5 ppm (by volume).

  1. It is found in some minerals, where it is produced by radioactive elements that decay by alpha particle emission (see below).
  2. Helium is the second most abundant element in the universe (23% by mass); hydrogen and helium together make up 99% of the “normal” matter of the universe.
  3. Of course, there’s also “dark matter” and “dark energy” to worry about, but that’s another story.) Hydrogen, helium, and trace amounts of lithium were produced at the beginning of the Universe in the Big Bang, and became concentrated into stars by the force of gravity.

The fusion of hydrogen atoms in stars to produce helium produces huge amounts of energy; the energy in sunlight is captured by plants in photosynthesis, and drives most of the chemistry of living organisms. The most common isotope of helium, helium-4, consists of two protons and two neutrons in the nucleus, surrounded by two electrons.

An alpha particle is a type of radiation emitted by some radioactive nuclei, which consists of two protons and two neutrons, having a 2+ charge; when an alpha particle is emitted by a radioactive element, it quickly picks up two electrons from its environment, becoming a helium atom. Helium is found along with some radioactive minerals that decay by alpha particle emission, however the concentration of helium in these minerals is very low.

The main source of helium is from natural gas, where it is separated out from the other components by fractional distillation. Helium liquefies at 4.18 K (-268.97 ° C); at 2.17 K it becomes a superfluid, in which all viscosity (resistance to flow) is lost.

Some materials become superconductors when immersed in liquid helium; in these materials, there is no resistance to the flow of electricity. Superconducting magnets are used for an important medical imaging technology called Magnetic Resonance Imaging (MRI), which allows images of tissues and organs to be obtained.

A related technology is used by chemists to obtain information that can be used to deduce the structures of molecules; this technique is called Nuclear Magnetic Resonance (NMR); the two technologies are basically the same, but the term “nuclear” is avoided in the medical application because of its unpleasant associations (even though there is no nuclear radiation involved).

Helium is also used in blimps, where the combination of being lighter than air and nonflammable makes it much safer than hydrogen (as demonstrated in the explosion of the ). It is also used in deep-sea diving, since helium is less soluble in the bloodstream than nitrogen, and reduces the risk of the diver suffering nitrogen narcosis, high pressure nervous syndrome (HPNS), or the bends.

Breathing helium gas causes the voice to become higher pitched because helium is less dense than air, changing the frequency of the sound waves generated in the larynx. (Ne, Z=10). Neon is a colorless, odorless, unreactive gas which liquefies at -246,1° C (27.1 K).

Neon was discovered in 1898 by Sir William Ramsay (see entry on Argon below) and his assistant Morris Travers while working with a sample of krypton. The name comes from the Greek word for “new,” neos, It is found in the Earth’s crust at a concentration of 70 ppt, making it the 80th most abundant element; it is found in the atmosphere at a concentration of 18 ppm (by volume).

Neon which is used commercially is extracted from liquid air by fractional distillation. Neon is used primarily in neon lights ; stimulating neon with electricity causes it to emit an intense red light. Other noble gases are used in “neon lights” as well, to produce different colors.

Neon is also used in some underwater breathing mixtures; liquid neon is used in low-temperature cooling. (Ar, Z=18). Argon is a colorless, odorless, unreactive gas which liquefies at -185.8 ° C (87.3 K). It is found in the Earth’s crust at a concentration of 1.2 ppm (produced by the radioactive decay of potassium-40), making it the 56th most abundant element; it is found in the atmosphere at a concentration of 0.93% (by volume).

Argon which is used commercially is extracted from liquid air by fractional distillation. Even though argon makes up almost 1% of the Earth’s atmosphere, it was not identified until 1894 by John William Strutt, 3rd Baron Rayleigh (Nobel Prize in Physics, 1904) and Sir William Ramsay (Nobel Prize in Chemistry, 1904).

  • Argon had been observed before (by Henry Cavendish in 1785), but it had not been identified as an element.
  • Because of its unreactivity, it was named for the Greek word for “idle,” argos,
  • When argon was discovered, it didn’t fit with the reactivities of any other element on the periodic table, and chemists realized that there might be a whole family of previously-unrecognized elements, which we now recognize as Group 8A.
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Argon is used in light bulbs because it is inert to the hot metal of the bulb filament; the filament would burn out much faster in air or even pure nitrogen. It is also used in metal refining, some “neon” lights (argon produces a blue light), some food packaging (to provide an inert atmosphere to reduce spoilage), in the tires of some luxury cars in place of air, and in lasers used in eye surgery.

  • Argon is produced by the radioactive decay of potassium-40; the potassium-40 nucleus undergoes electron capture to produce the stable argon-40 nucleus.
  • The ratio of potassium-40 to argon-40 in some rocks can be used to determine the age of the rock.
  • Recently, the first argon compound, argon fluorohydride (HArF), was, which is stable up to 27 K.

(I’m waiting for hydrogen to be replaced by boron: I think a molecule that spells out “BArF” would be worth investigating. Or not.) (Kr, Z=36). Krypton is a colorless, odorless, unreactive gas which liquefies at -153.2 ° C (119.9 K). It is found in the Earth’s crust at a concentration of 10 ppt, making it the 81st most abundant element; it is found in the atmosphere at a concentration of 1 ppm (by volume).

Krypton which is used commercially is extracted from liquid air by fractional distillation. Krypton was discovered in 1898 by Sir William Ramsay and his assistant, Morris Travers, in a sample of argon gas extracted from the atmosphere. The name “krypton” is derived from the Greek word kryptos, meaning “hidden” (which has nothing to do with the home planet of Superman).

Krypton is used in some “neon” lights, producing a violet color when electricity is passed through it. Radioactive kyrypton-85 is produced in nuclear reactors and nuclear processing plants; monitoring krypton-85 in the atmosphere allowed the United States to monitor how much nuclear material the Soviet Union was using.

  • Ze, Z=54).
  • Xenon is a colorless, odorless, unreactive gas which liquefies at -111.7 ° C (161.4 K).
  • It is found in the Earth’s crust at a concentration of 2 ppt, making it the 83rd most abundant element; it is found in the atmosphere at a concentration of 90 ppb (by volume).
  • Xenon which is used commercially is extracted from liquid air by fractional distillation.

Xenon was also discovered by Ramsay and Travers in 1898. The name is derived from the Greek word for “stranger,” xenos, Xenon lights glow with a blue light, and also emits some low-frequency ultraviolet light. Xenon lights are used in tanning beds, biocidal lamps used in food preparation, car headlights, flash lighting on cameras, strobe lights used in high-speed photography, and has been tested for use in space travel in ion-propulsion engines (such as the experimental NASA spacecraft ).

  • Rn, Z=86).
  • Radon is a colorless, odorless, radioactive gas which liquefies at -61.8 ° C (211.3 K).
  • It is found in the Earth’s crust in only trace amounts, and is one of the ten least abundant elements; it is found in the atmosphere at a concentration of 10 -9 ppt (by volume).
  • Radon was discovered in 1900 by Friederich Ernst Dorn while investigating “radium emanation” (first observed by Marie and Pierre Curie), a gas found in sealed vessels of radium.

The name is a variation on the name of the element radium. It is produced in the radioactive decay of uranium and thorium, which in a series of steps decay into radium, which then undergoes alpha-decay to produce radon. The most common isotopes of radon are radon-220 and radon-222, which have half-lives of 55.6 seconds and 3.82 days, respectively.

Although chemically unreactive, when radon is produced, it can escape from the ground in the gas form, and collect in basements, or other contained areas. Radon is an alpha-particle emitter; while alpha particles can be blocked easily, if the radon gas is inhaled, and undergoes alpha decay in the lungs, it produces an isotope of polonium, which is a solid, as are all of its decay products, some of which have half-lives of over 20 years.

Having alpha-particle emitters inside the lungs leads to a greatly increased risk of lung cancer, accounting for about 10% of all reported cases of lung cancer.

Why are group 18 elements called?

The elements present in Group 18 have their valence shell orbitals completely filled. Hence, they react with a few elements only under certain conditions. Therefore, they are known as noble gases.

Are there 18 groups in the modern periodic table?

In chemistry, a group (also known as a family) is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table ; the 14 f-block columns, between groups 2 and 3, are not numbered.

What is Group 17 and group 18 periodic table?

Group 17 elements are called halogens. Group 18 elements are called noble gases.

What are the groups 1 2 13 18 on the periodic table?

Group numbers

  • The group number is an identifier used to describe the column of the standard periodic table in which the element appears.
  • Groups 1-2 termed s-block elements.
  • Groups 1-2 (except hydrogen) and 13-18 are termed main group elements.
  • Groups 3-12 are termed d -block elements.

Groups 3-11 are termed transition elements. Transition elements are those whose atoms have an incomplete d-subshell or whose cations have an incomplete d-subshell. Groups 13-18 termed p-block elements. Main group elements in the first two rows of the table are called typical elements.

  • Group 1: alkali metals
  • Group 2: alkaline earth metals
  • Group 11: coinage metals (not an IUPAC approved name)
  • Group 15: pnictogens (not an IUPAC approved name)
  • Group 16: chalcogens
  • Group 17: halogens
  • Group 18: noble gases

In addition, groups may be idenitifed by the first element in each group – so the Group 16 set of elements is sometimes called the oxygen group. Groups And Periods On The Periodic Table Image showing periodicity of group numbers for group 13 chemical elements.