Chem Module 3 Review
A metal ion with a net +3 charge has five electrons in the 3d subshell. Identify the metal
Fe, iron
how does the size of an atom change when it becomes a) an anion b) a cation
Ionic radius is the radius of a cation or anion a) when atom gains one or more electrons and becomes anion, its radius increases due to increased electron-electron repulsion b) when atom loses electron and becomes cation, its radius decreases due in part to reduction in electron-electron repulsion in valence shell
In atoms with more than one electron, the electrons are simultaneously
attracted to the nucleus and repelled by one another
If an atom loses one or more electrons, it has a net positive charge and is known as a
cation
An anion with a net -2 charge has a total of 36 electrons. Identify the element from which the anion is derived
selenium, Se
Whats the relationship among elements in same group in the periodic table?
similar physical and chemical properties
Why are electron affinity measurements made with gaseous atoms?
since in the solid or liquid states, their energy levels would be changed by contract w other atoms or molecules
What do we mean when we say 2 ions or an atom and an ion are isoelectronic?
their electron config are the same
For ions of transition elements the transition elements, the 3d orbitals are ___ in energy than 4s orbitals. Therefore, the electrons most easily lost are ____
those in outermost principal energy level, the ns
either have incompletely filled d subshells or readily lose electrons to achieve incompletely filled d subshells
transition metals
elements are arranged in periodic table based on the
type of subshells containing the outermost electrons
outermost electrons of an atoms
valence electrons
distance between the nucleus of an atom and its valence shell
atomic radius
valence electrons determine how
atoms interact with one another
explain what causes diagonal relationship
- similarity of charge densities of their cations - therefore, they exhibit some of the same chemical properties. Each of these pair is said to exhibit diagonal relationships
Ionization energy is always positive quantity, whereas electron affinity may be either positive or negative
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Explain why ionization energy always greater than the first ionization energy always greater than the first ionization energy for any element? What types of elements have highest ionization energies and what types have lowest ionization energies?
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77
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78
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79
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94
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Explain why alkali metals have a greater affinity for electrons than alkaline earth metals?
Alkali metals have valence electron config of ns¹, so they can accept another electron in ns orbital. On the other hand, alkaline earth metals have valence electron config of ns2, so they have little tendency to accept another electron unless it goes into a higher energy p orbital
Explain trend in electron affinity from aluminum to chlorine
Aluminum and chlorine belong to Period 3 of periodic table; EA increases from Al3+ to Cl-. This is because of the increase in the effective nuclear charge from left to right
Explain why isoelectronic series cant include more than one member of the same group?
An isoelectronic series cannot include more than one member of the same group bc they vary in electronic config and therefore would have different numbers of electrons
Use the third period of the periodic table as an example to illustrate the change in first ionization energies of the elements as we move from left to right. Explain the trend.
Apart from small irregularities, ionization energies of elements in period increases with increasing atomic number this trend refers to increase in effective nuclear charge from left to right. A larger ENC means more tightly held outer electron, and hence a higher first ionization energy. Thus, in the third period, sodium has the lowest and neon has the highest first ionization energy
Explain why the atomic radius of S is larger than that of O but smaller than that of P
As we move down a group, inner electrons shield the outer electrons and quantum number n increases; the atom gets larger in moving down from O to S. As we move across a period, shielding doesnt change so more positive attraction is attraction is experienced by outer electrons; the atoms gets smaller in moving across from P to S.
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Be and Mg are the two alkaline earth metals with diagonal relationships with Al of Group 3 and Li of Group 1, respectively
Specify which of the following elements you would expect to have the greatest electron affinity: He, K, Co, S, Cl
Cl
Arrange the following atoms in order of increasing atomic radius: Si, Mg, Cl, P, Al
Cl < P < Si < Al < Mg
A M²⁺ ion derived from a metal in the first transition metal series has four electrons in the 3d subshell. What element might M be
Cr, chromium
Arrange the following in order of increasing first ionization energy: Na, Cl, Al, S, and Cs
Cs < Na < Al < S < Cl
Explain which of the following cations is larger and why: Cu⁺ or Cu²⁺
Cu+ ion is larger than the Cu2+ ion because it has one more electron
Considering their electron affinities, do you think it is possible for the alkali metals to form an anion like M⁻, where M represents an alkali metal?
Electron affinity values generally increase across a row on the periodic table. Based on the low electron affinity values at the start of each row, we wouldnt expect the alkali metals to accept another electron and form anions
Use the second period of the periodic table as an example to show the size of atoms decreases as we move from left to right. Explain the trend
For the second period, the atomic radius of Li is largest bc 2s electron is well shielded by the filled 1s shell. The effective nuclear charge that the outermost electrons feel increases across period as a result of incomplete shielding by electrons in same shell Consequently, orbital containing the electrons is the compressed, and the atomic radius decreases
State whether each of the following properties of the main group elements generally increases or decreases from left to right across period
From left to right across a period: metallic character decreases, atomic size decreases, ionization energy increases (w some exceptions) acidity of oxides inceases
State whether each of the following properties of the main group elements generally increases or decreases from top to bottom within a group
From top to bottom within a group: metallic character increases, atomic size increases, atomic size increases, ionization energy decreases, acidity of oxides decreases
In general, the first ionization energy increases from left to right across given period. Aluminum, however, has a lower first ionization energy than magnesium. Explain
Group 3A all have single electrons in outermost p subshell, which is well shielded from nuclear charge by inner electrons and the ns2 electrons. Less energy is needed to remove single p electron than to remove a paired s electron from the same principal energy level (such as for Mg).
Hydrogen forms the ___ and ___ ion. please describe what each resembles
H+ ions resembles the alkali metals H- ions resembles the halogens
Arrange the following in order of increasing first ionization energy: F, K, P, Ca, and Ne
K < Ca < P < F < Ne
grouped elements based on their properties and correctly predicted the properties of elements that hadnt been discovered yet
Mendeleev's periodic table
Metal, nonmetal or metalloid: Sb, Kr, Co, Na, Al, F, Sr, As, Br, Ge
Metals: Co, Na, Sr, Al Non: F, Br, Kr Metalloids: As, Ge, Sb
List the following ions in order of increasing ionic radius: N³⁻, Na⁺, F⁻, Mg²⁺, O²⁻
Mg²⁺ < Na⁺ < F⁻ < O²⁻ < N³⁻
The first and second ionization energies of K are 419 and 3052 kJ/mol, and those of Ca are 590 and 1145 kJ/mol, respectively. Compare their values and comment on the differences
Moving across row of periodic table, the electrons added to counterbalance the increasing nuclear charge dont completely shield outer electrons from nucleus Therefore, Zeff increases across a row so we expect the first ionization energy for calcium to be higher. For potassium, however, the second electron must come from the atoms noble gas core, which accounts for the much higher second ionization energy
Is it possible for atoms of one element to be isoelectronic with the atoms of another element? Explain
No, neutral atoms have same number of electrons as protons. Since the number of protons determines identity of atom, it cant be isoelectronic w atom of another element
Which is the smallest atom in Group 6A?
Oxygen
Explain which of the following anions is larger and why: Se²⁻ or Te²⁻
Since atomic radius increases going down a column in periodic table, Te2- must be larger than Se2-
Which is the largest atom in the third period of the periodic table
Sodium
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When charges have opposite signs, F is negative, indicating an attractive force between the objects. When the charges have the same signs, F is positive, indicating a repulsive force
Write the ground-state electron configurations of the following ions: a) Li⁺ b) H⁻ c) N³⁻ d) F⁻ e) S²⁻ f) Al³⁺ g) Se²⁻ h) Br⁻
a) 1s² b) 1s² c) 1s²2s²2p⁶ d) 1s²2s²2p⁶ e) [Ne] 3s²3p⁶ f) [Ne] g) [Ar]4s²3d¹⁰4p⁶ h) [Ar]4s²3d¹⁰4p⁶
name a) halogen in fourth period b) element similar to phosphorus in fourth period c) metal in fifth period w lowest ionization energy d) element with atomic number smaller than 20 and similar to strontium
a) Br, bromine b) N, nitrogen c) Rb, rubidium d) Mg, magnesium
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a) C and B⁻ are isoelectronic b) Mn²⁺ and Fe³⁺ are isoelectronic c) Ar and Cl⁻ are isoelectronic d) Zn and Ge²⁺ are isoelectronic
Indicate which is smaller a) Cl or Cl⁻ b) Na or Na⁺ c) O²⁻ or S²⁻ d) Mg²⁺ or Al³⁺ e) Au or Au³⁺
a) Cl b) Na+ c) O2- d) Al3+ e) Au3+
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a) Cr³⁺ b) Sc³⁺ c) Rh³⁺ d) Ir³⁺
Arrange the elements in each of the following groups in order of increasing electron affinity: a) Li, Na, K b) F, Cl, Br, I
a) K < Na < Li b) I < Br < F < Cl
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a) K⁺ b) Cu⁺ c) In⁺ d) Cs⁺
ON the basis of their positions in the periodic table, select the atom with the larger atomic radius in each of the following pairs: a) Mg, P b) Sr, Be c) As, Br d) Cl, I e) Xe, Kr
a) Mg is larger, its to the left of P in Period 3 b) Sr is larger, Its below Be in Group 2A c) As is larger, its to the left of Br in Period 4 d) I is larger, its below Cl in Group 7A e) Xe is larger, its below Kr in Group 8A
Write the ground-state electron configurations of the following ions: a) Sc³⁺ b) Ti⁴⁺ c) V⁵⁺ d) Cr³⁺ e) Mn²⁺
a) [Ar] b) [Ar] c) [Ar] d) [Ar]3d³ e) [Ar]3d⁴
Write the ground-state electron configurations of the following ions: a) Fe²⁺ b) Cu²⁺ c) Co²⁺ d) Mn²⁺
a) [Ar]3d⁶ b) [Ar]3d⁹ c) [Ar]3d⁷ d) [Ar]3d⁵
Write the ground-state electron configurations of the following ions: a) Ni²⁺ b) Cu⁺ c) Ag⁺ d) Au⁺ e) Au³⁺
a) [Ar]3d⁸ b) [Ar]3d¹⁰ c) [Kr]4d¹⁰ d) [Xe]4f¹⁴5d¹⁰ e) [Xe]4f¹⁴5d⁸
Write the ground-state electron configurations of the following ions: a) Rb⁺ b) Sr²⁺ c) Sn²⁺ d) Te²⁻ e) Ba²⁺ f) In³⁺ g) Tl⁺ h) Tl³⁺
a) [Kr] b) [Kr] c) [Kr]5s²4d¹⁰ d) [Kr]5s²4d¹⁰5p⁶ e) [Xe] f) [Kr]5d¹⁰ g) [Xe]6s²4f¹⁴5d¹⁰ h) [Xe]4f¹⁴5d¹⁰
Write the ground-state electron configurations of the following ions: a) Na⁺ b) Mg²⁺ c) Cl⁻ d) Ca²⁺
a) [Ne] b) same as (a) c) [Ar] d) same as (c)
A cation with a net +3 charge is shown to have a total of 10 electrons. Identify the element from which the cation is derived
aluminum, Al
If atom gains electrons, it has a net negative charge and is known as
anion
Explain why, for cation and an anion that are isoelectronic, the anion is larger than the cation
anions are larger than the cations because they have smaller nuclear charges
Atomic radius ___ from left to right across a period
decreases
refers to the similarities between pairs of elements in different groups and periods of the periodic table
diagonal relationship
actual magnitude of positive charge that is experienced by an electron in the atom
effective nuclear charge
While moving from top to bottom in a group, valence electrons are
effectively shielded by the core electrons
energy released when an atom in the gaseous phase accepts an electron
electron affinity For example,when a mole of gaseous chlorine atom accepts a mole of electrons, 349 kJ/mol of energy are released
Why is the radius of the lithium atom considerable larger than the radius of the hydrogen atom?
electron configuration of lithium is 1s²2s¹. The two 1s electrons shield the 2s electron effectively from nucleus. Consequently, the lithium atom is considerably larger than the hydrogen atom.
nonmetals typically ___ electrons to form ___, and they tend to form ____
gain, anion, molecular compounds
There is a ____ in effective nuclear charge from left to right across a period than there is from top to bottom in a group
greater increase
main group elements are those in
group 1a through 7a
Atomic radius ____ from top to bottom in a group
increases
While moving left to right across period, Zeff ___ because ___
increases steadily, the number of core electrons remains the same
minimum energy required to remove an electron from an atom in the gas phase
ionization energy
metals typically ___ electrons to form ___, and they tend to form ____
lose, cation, ionic compounds
How does the electron configuration of ions derived from main group of elements give them stability?
main group elements tend to form ions that have half-filled or completely filled valence shells
atomic radius can be defined in two ways: ____ which is half the distance between the nuclei of 2 adjacent, identical metal atoms ____ which is half the distances between adjacent identical nuclei that are connected by chemical bond
metallic radius, covalent radius
tend to be shiny, lustrous, malleable, ductile, and conducting (for both heat and electricity)
metals
tend to be brittle and not good conductor (for either heat and electricity)
nonmetals