Trends In The Periodic Table

What are the 5 trends of the periodic table?

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  • Periodic trends are specific patterns that are present in the periodic table that illustrate different aspects of a certain element, including its size and its electronic properties. Major periodic trends include: electronegativity, ionization energy, electron affinity, atomic radius, melting point, and metallic character, Periodic trends, arising from the arrangement of the periodic table, provide chemists with an invaluable tool to quickly predict an element’s properties. These trends exist because of the similar atomic structure of the elements within their respective group families or periods, and because of the periodic nature of the elements.

    How do you find trends on the periodic table?

    Identifying Periodic Trends – High School Chemistry Which of the following atoms is the largest? Possible Answers: Correct answer: Potassium Explanation : Atom size is determined by the number of shells and how many protons and electrons are present in the atom.

    Any atom in a higher number period (row) is larger than any atom in a lower number period, since the number of electron shells increases as the number of the period increases. Within the same period, atoms get smaller as you move towards the right. This is because the atomic number increases, increasing the number of protons in the nucleus.

    These protons attract the surrounding electrons, pulling them in closer, and shrinking the total size of the atom. In general, atomic radius will increase as you move down and to the left. This makes helium the smallest atom and francium the largest. Which ion of nitrogen is the largest? Possible Answers: Correct answer: Explanation : Ions of atoms vary in their size. When an atom gains electrons the atomic size increases, and when an atom loses electrons the atomic size decreases. Nitrogen with a formal charge of negative three will have the largest size because it has the most electrons.

    Remember that adding electrons will cause a negative ion, while removing electrons will cause a positive ion. Which of the following values will decrease as you move left to right in a period of the periodic table? Possible Answers: Correct answer: Atomic radius Explanation : Moving left to right on the periodic table causes an increase in atomic number (number of protons) as well as electron affinity and electronegativity.

    Atomic radius, however, will decrease when moving left to right. As more protons are added to the nucleus, they have a stronger attraction to the electrons. This pulls the electrons closer to the nucleus, resulting in a smaller atomic radius. Elements that have similar properties will have the same _ on the periodic table.

    Possible Answers: Explanation : The periodic table is set up so that we can quickly tell which elements will react in a similar chemical fashion. The elements from the same group, that is the same column, will have similar properties. This is due to the same number of valence electrons in the outer shell.

    Elements from which group in the periodic table will have the lowest first ionization energies? Possible Answers: Correct answer: Alkali metals Explanation : Ionization energy is the amount of energy needed to remove an electron from an atom. Alkali metals only need to lose one electron in order to achieve the stable noble gas octet.

    1. As a result, the loss of this electron requires very little energy since the resulting ion is favorably stable.
    2. This property causes alkali metals (found in group I) to have the lowest first ionization energies.
    3. Which of these elements has the smallest atomic radius? Possible Answers: Explanation : The trend for atomic radius is as follows: atomic radius increases from right to left within a row and from top to bottom within a group on the periodic table.

    Which of these elements is the most electronegative? Possible Answers: Explanation : Fluorine is the most electronegative element. The trend for electronegativity is as follows: electronegativity increases from left to right within a row and from bottom to top within a group of the periodic table.

    • Which of these elements is the least electronegative? Possible Answers: Explanation : Francium is the least electronegative element.
    • The trend for electronegativity is as follows: electronegativity increases from left to right within a row and from bottom to top within a group of the periodic table.
    • Which of these elements has the largest atomic radius? Possible Answers: Explanation : The trend for atomic radius is as follows: atomic radius increases from right to left within a row and from top to bottom within a group on the periodic table.

    Which of these elements has the greatest ionization energy? Possible Answers: Explanation : Lithium has the greatest ionization energy because it is the smallest of the options available. The smaller an element/atom is, the closer to the nucleus of the atom the valence electrons are. Mr. Henderson Certified Tutor Swarthmore College, Bachelor of Science, Engineering. MBU, Master of Science, Education. Amaris Certified Tutor University of Alabama at Birmingham, Bachelor of Science, Chemistry. Anmol Certified Tutor Rutgers University-New Brunswick, Current Undergrad, Cellular Biology and Neuroscience. If you’ve found an issue with this question, please let us know.

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    Charles Cohn Varsity Tutors LLC 101 S. Hanley Rd, Suite 300 St. Louis, MO 63105 Or fill out the form below: : Identifying Periodic Trends – High School Chemistry

    What are the trends in the periodic table across a group?

    Periodic Trends of Properties of Elements In Periodic Table – Modern periodic law is the base of periodic trends of properties of elements in the modern periodic table. Following properties of elements show a very clear periodic trend in the periodic table –

    Atomic Radius Ionisation energy Electron affinity Electronegativity Valence electrons Valency Metallic character of the elements Non – metallic character of the elements Reactivity of elements Melting and boiling points of elements

    Now, understand the trends of properties in detail by knowing the reason for the variation of properties.

    Atomic Radius

    Atomic radius is the distance between the centre of the nucleus of an atom to its outermost shell. The periodic trend of atomic radius across a period – As we move from left to right in a period, atomic radius gradually decreases. Reason – As we move left to right in a period the atomic number of the elements increases so nuclear charge increases while the number of shells in elements remains the same.

    Elements of 2 nd period Li Be B
    Atomic Number 3 4 5
    Nuclear Charge or Number of Protons In The Nucleus 3 4 5
    Number of Shells 2 2 2
    Atomic Radius (In Pm) 152 106 88

    Exceptional Behaviour – Noble gases show exceptional behaviour. The atomic radii of inter gases suddenly increase as compared to its predecessor halogen atom. The reason for this type of exceptional behaviour is that atomic radius refers to van der Waals radius in the case of noble gases while in the case of other elements it refers to the covalent radius.

    Ionisation Energy

    Ionisation energy is the amount of energy required to remove one electron from an atom. First ionisation energy is the amount of energy required to remove one outermost electron from an atom. The periodic trend of ionisation energy across a period – As we move from left to right in a period, ionisation energy gradually increases.

    Elements of 3 rd period Al Si P
    Atomic Number 13 14 15
    Nuclear Charge or Number of Protons In The Nucleus 12 14 15
    Number of Shells 3 3 3
    First Ionisation Energy 577.5 786.5 1011.8

    Exceptional Behaviour – Beryllium possesses more first ionisation energy than Boron. Because beryllium has a half-filled s – orbital and more energy is required to remove an electron from half or completely filled orbitals. That is why noble gases also show exceptionally high ionisation energies.

    Electron Affinity

    The amount of energy required to add an electron to an atom is called the electron affinity of that atom. In other words, electron affinity is the change in energy when an electron is added to the atom and a neutral atom changes into a negative ion. The periodic trend of electron affinity across a period – As we move from left to right in a period, electron affinity gradually increases.

    Elements of 4 th period Ti V Cr
    Atomic Number 22 23 24
    Nuclear Charge or Number of Protons In The Nucleus 22 23 24
    Electron Affinity (Ev) 0.075 0.527 0.675

    Exceptional Behaviour – Beryllium does not form a stable anion, so it releases less energy than boron by adding an electron. While nitrogen neither releases nor requires a significant amount of energy on adding an electron so it has electron affinity almost equal to zero. Across a Group – on moving top to bottom in a group, electron affinity gradually decreases.

    Electronegativity

    Electronegativity is a measure of the ability of an atom or molecule to attract pairs of electrons in the context of a chemical bond. Across A Period – As we move left to right across a period, electronegativity increases in the periodic table. Fluorine is the most electronegative element.

    Elements of 3 rd period Na Mg Al
    Atomic Number 11 12 13
    Nuclear Charge or Number of Protons In The Nucleus 11 12 13
    Electronegativity (Pauling Scale) 0.93 1.31 1.61

    Across A Group – As we move top to bottom in a group, electronegativity decreases.

    Valence Electrons

    Electrons present in the outermost shell of an atom are called valence electrons of that atom. Across A Period – As we move left to right across a period in the periodic table, the number of valence electrons increases. Example –

    Elements of 3 rd period Na Mg Al
    Atomic Number 11 12 13
    Electronic Configuration 2,8,1 2,8,2 2,8,3
    Valence Electrons 1 2 3

    Across A Group – Across a group, valence electrons remain constant. It means elements present in the same group have the same number of valence electrons. For example, hydrogen, lithium, and sodium elements are present in the 1 st group and have the same number of valence electrons which is one.

    Valency

    Valency is the combining capacity of an atom. Across a Period – on moving left to right across a period in the periodic table, first valency increases then decrease. Example –

    Elements of 2 nd period Li Be B C N o F Ne
    Atomic Number 3 4 5 6 7 8 9 10
    Electronic Configuration 2,1 2,2 2,3 2,4 2,5 2,6 2,7 2,8
    Valency 1 2 3 4 3 2 1 0

    Across A Group – There is no change in valency across a group. Elements of the same groups show the same valency.

    Metallic Character of The Elements

    Across a Period – As we move left to right across a period in the periodic table, the metallic character of elements decreases. Example –

    Elements of 2 nd period Li Be B C N o F Ne
    Metallic Character Metal Metal Metalloid Nonmetal Nonmetal Non metal Nonmetal Nonmetal

    Across a Group – As we move top to bottom in a group of the periodic table, the metallic character of elements increases.

    Non-Metallic Character of The Elements

    Across a Period – As we move left to right across a period in the periodic table, the non-metallic character of elements increases. Example –

    Elements of 2 nd period Li Be B C N o F Ne
    Nonmetallic Character Metal Metal Metalloid Nonmetal Nonmetal Nonmetal Nonmetal Nonmetal

    Across a Group – As we move top to bottom in a group of periodic tables, non-metallic character decreases. Example –

    Group 15 Nonmetallic Character
    N Nonmetal
    P Nonmetal
    As Metalloid
    Sb Metalloid
    Bi Metal

    ul> Reactivity of Elements

    The reactivity of metals depends on their electropositive character. So, more is the metallic character, more is the electropositive nature of the element and more is its reactivity. As metallic character decreases across a period left to right, reactivity also decreases.

    Elements of 3 rd period Na Mg Al Si P S Cl Ar
    Group 1 2 13 14 15 16 17 18
    Reactivity Very reactive Reactive Reactive Least reactive Reactive Reactive Very reactive Inert
    Reactivity decreases 🡪 Reactivity increases🡪
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    ul> Melting And Boiling Points of Elements

    Melting and boiling points of metals decrease gradually from top to bottom in a group. While melting and boiling points of nonmetals increase on moving from top to bottom in a group of the periodic table.

    How many periodic trends are there?

    Periodic Table Trends – Physical Chemistry Which of the following trends decreases as you move from left to right on the periodic table? Possible Answers: Correct answer: Atomic radius Explanation : Although it may seem counterintuitive, atomic radius does decrease from left to right on the periodic table.

    • The reason for this is because the added positive charge in the nucleus causes the elctrons to be pulled more strongly towards the center, which decreases the atomic radius.
    • Which of the following atoms has the greatest electronegativity? Possible Answers: Explanation : Electronegativity values become greater as you move up and to the right on the periodic table.

    Of the four atoms listed, sulfur is the highest up and farthest to the right, giving it the greatest electronegativity. Which of these is in order of increasing ionization energy? Possible Answers: Correct answer: Explanation : Ionization energy is the amount of energy that an atom in the ground state must absorb to emit an electron. Upon ionization, a cation is formed. Ionization energy increases from bottom to top within a group, and from left to right within a row of the periodic table which is the opposite trend that atomic radius follows. Correct answer: Explanation : All of these atoms are in group VII. Within a group, atomic radii increase from top to bottom due to the increased number of electron shells. Which of the following lists is in order of increasing ionization energy? Possible Answers: Correct answer: Explanation : Ionization energy is the amount of energy that an atom in the ground state must absorb to emit an electron.

    Upon ionization, a cation is formed. Ionization energy increases from bottom to top within a group and from left to right across a period in the periodic table which is the opposite trend that atomic radius follows. Referring to the periodic table, it can be seen that helium has the highest ionization energy of those in the list.

    As you progress from left to right along the periodic table, the electronegativity _ and the atomic size _, Possible Answers: decreases, increases increases, decreases decreases, decreases increases, increases Correct answer: increases, decreases Explanation : There are four main periodic trends: electronegativity, atomic size, ionization energy, and electron affinity.

    Electronegativity measures how easily an atom can attract an electron to form a covalent bond, atomic size (as the name implies) measures the size of the atom, ionization energy measures the amount of energy required to remove an electron, and electron affinity measure the amount of energy released upon absorption of an electron.

    Electronegativity increases as we go towards the top right of the periodic table (Fluorine has the highest electronegativity), atomic size increases as we go towards the bottom left, ionization energy increases as we go towards top right, and electron affinity increases as we go towards top right.

    • This means that as we go left to right, electronegativity, ionization energy and electron affinity will increase.
    • A researcher is analyzing two unknown molecules, molecule A and B.
    • He identifies that both molecules have the following structure, where is an unknown atom.
    • Upon further analysis, he observes that from molecule A is found towards the bottom left of the periodic table whereas from molecule B is found towards the top right.

    What can you conclude from the given information? Possible Answers: Molecule B can traverse cell membranes easier Molecule A is more soluble in water Correct answer: None of these Explanation : To answer this question, we need to look at the electronegativity periodic trend.

    • Recall that electronegativity increases as you go towards the top and right of the periodic table.
    • For example, fluorine (the most top-right, non-noble gas element on the periodic table) has the highest electronegativity (note that noble gases have no reactivity, so electronegativity is not measured for them).

    The question states that in molecule B is at the top right. This means that has the higher electronegativity. The polarity of a molecule is calculated using the electronegativity differences between the atoms in the molecule. The higher the electronegativity difference, the more polar.

    1. Since in molecule B has the higher electronegativity, molecule B will be more polar (larger electronegativity difference) than molecule A.
    2. Recall that like dissolves like.
    3. Water is a highly polar molecule; therefore, polar molecules will dissolve more easily in water (in our case, molecule B).
    4. To traverse the hydrophobic interior of a cell membrane, a molecule should be nonpolar; therefore, molecule A will have an easier time traversing the membrane.

    Which of the following properties follows the same periodic trend as electron affinity? Possible Answers: Number of valence electrons Correct answer: Electronegativity Explanation : Electron affinity is the energy released when an atom gains an electron.

    The amount of energy released is higher if the atom readily accepts the electron and has high affinity, or ‘attraction’, for the electron. As we go towards the right on the periodic table, elements like to gain electrons to complete their octet; therefore, electron affinity increases as we go towards the right.

    As we go down, electron affinity decreases because of increases in atomic size. This means that the electron affinity increases as we go top-right. The only other listed periodic trend that increases as we go top-right is electronegativity. Note that number of valence electrons and polarity are generally not considered periodic trends.

    • Which of the following is true regarding ionization energy? I.
    • The ionization energy increases as we go down a column on periodic table II.
    • The ionization energy of the electron in the outermost shell of Lithium is higher than the ionization energy of electrons in innermost electrons. III.
    • The ionization energy increases as we go right on periodic table Possible Answers: Explanation : Ionization energy is the energy required to remove an electron.

    Ionization energy decreases as we go towards the bottom-left on the periodic table. As we go left on periodic table the ionization energy decreases because electrons in the outermost shell are readily willing to give up their electrons to complete the octet.

    1. For example, lithium has one valence electron in its outermost shell ().
    2. The lithium atom will readily give up its one valence electron to complete its octet (or doublet in the case of lithium because the innermost shell only contains two electrons).
    3. Note that the ionization energy to remove innermost electrons of lithium is extremely high.

    This occurs because it takes a lot of energy to destabilize the octet. The ionization energy decreases as we go towards the bottom of the periodic table because the atomic size increases, making it easier to remove the electron. The radius of is _ than that of and the radius of is _ than that of,

    Possible Answers: the same size, the same size Correct answer: smaller, larger Explanation : Negative ions contain larger radii than their atom counterparts. When an atom becomes an anion, the valence shell becomes crowded with electrons. This results in an increase in repulsive forces, thereby increasing the atomic radius.

    Conversely, positive ions contain smaller radii than their atomic counterparts. When a cation is formed, the protons in the nucleus outnumber the electrons surrounding the atom. This results in a stronger pull towards the nucleus, which in turns reduces the atomic radius.

    1. Also, recall that it is the valence electrons that are removed in cations, thus the cationic form may have a lower principal quantum number.
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    What are the trends in reactivity?

    The farther to the left and down the periodic chart you go, the easier it is for electrons to be given or taken away, resulting in higher reactivity. Period – reactivity increases as you go from the left to the right across a period. Group – reactivity decreases as you go down the group.

    What are the trends in Group 7 of the periodic table?

    Halogens – trend in reactivity – As you look at the trend in reactivity of group 7, the reactivity of halogens decreases so fluorine is the most reactive halogen and astatine is the least reactive halogen. Halogens react to gain an electron so they become more stable,

    The atomic mass of the halogens increases, They increase in electron shells; so the atoms are larger as you go down the group. Therefore, the attraction of the outer electron to the nucleus decreases as you go down group 7. The number of electrons increase, There are more electrons shielding the positively charged nucleus from the outer electron. Therefore, the attraction of the outer electron to the nucleus decreases as you go down group 7.

    The weaker electrostatic attraction of the electron being gained to the positive nucleus, makes it harder for the atom to gain an electron and it decreases in reactivity in group 7.

    What are the 4 trends of the periodic table?

    Major trends are electronegativity, ionization energy, electron affinity, atomic radius, and metallic character. The existence of these trends is due to the similarity in atomic structure of the elements in their group families or periods and because of the periodic nature of elements.

    Why are periodic trends important?

    Learning Objectives – 1. Be able to state how certain properties of atoms vary based on their relative position on the periodic table. One of the reasons the periodic table is so useful is because its structure allows us to qualitatively determine how some properties of the elements vary versus their position on the periodic table.

    How does periodic trends affect the elements?

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  • Periodic trends affect bonding, because of how the elements are arranged on the periodic table. For example elements can be arranged by their electronegative, electron affinity, atomic radius, or ionization energy. Electronegative is the atoms ability to attract other bonded atoms. Electron affinity is an atoms ability to attract another atom. The atomic radius is the radius of an elements atom. Ionization energy is the energy it takes to remove an atom from another atom. Other periodic trends are when the attraction of the atoms for the pair of bonding electrons is different, this is polar covalent bonds. Properties in compounds are used to determine the type of bonding and structure, not just the elements being used. These different properties help group elements to make them either more available or less available for bonding.

    How do you explain trends in chemistry?

    Chemists observe patterns in different properties of elements as they are arranged in the periodic table. The covalent radius (a measure of how large individual atoms are) shows different trends if you are moving across a period or down a group. A comparison of the relative covalent radii of atoms is shown in the diagram below. Across a period from left to right, the covalent radius decreases. As you move from left to right across the periodic table, atoms have more electrons in their outer energy level and more protons in their nucleus. The greater attraction between the increased number of protons (increased nuclear charge) and electrons, pulls the electrons closer together, hence the smaller size.

    What are periodic properties?

    This phenomenon is known as the periodicity of elements. The periodic properties of elements occur due to the recurrence of similar electronic configuration that is having the same number of electrons in the outermost orbit. In a particular group, the number of valence electrons remains the same.

    What are the properties and uses of the group 7 elements?

    Melting point and boiling point – The halogens have low melting points and low boiling points. This is a typical property of non-metals. Fluorine has the lowest melting and boiling points. The melting and boiling points then increase as you go down the group. Melting and boiling points of Group 7 elements