Atomic Radii, Ionization Energy, and Ionic Radii Trends

Consider the most stable ions which are formed by the elements Cs, Ba, Te and I. Which element will form the ion with the largest radius? (Hint: the ions will be isoelectronic.)

Te

Consider the most stable ions which are formed by the elements Sr, In, Te and I. Which element will form the ion with the largest radius?

Te

From the data below Element First Ionization Energy 1 - 1310 kJ/mol 2 - 1011 kJ/mol 3 - 418 kJ/mol 4 - 2080 kJ/mol 5 - 947 kJ/mol which element is likely to be a metal?

3

Which of the following correctly rationalizes the increase in atomic radii down and to the left on the periodic table, based on what we discussed in class? 1. None of these. Atomic radii increase up and to the right. 2. Because the elements are easier to ionize, they have a larger electronegativity, and therefore their electron affinity is not sufficient to reduce atomic radii. 3. Larger elements have an increasing proportion of d and f orbitals, which are intrinsically larger than all of the s and p orbitals. 4. The elements are simply larger due to more protons and neutrons. 5. As you move to the left across a period, decreasing ENC means the outer electrons are less tightly held and can move further from the nucleus. As you move down a group, the electrons occupy orbitals that are further from the nucleus. 6. The periodic table was set up to group atoms by size to facilitate comparisons.

5. As you move to the left across a period, decreasing ENC means the outer electrons are less tightly held and can move further from the nucleus. As you move down a group, the electrons occupy orbitals that are further from the nucleus

Given the elements Cl, Ge, and K and the values 418, 1255, and 784 kJ/mol of possible first ionization energies, match the atoms with their first ionization energies.

Cl: 1255 kJ/mol; Ge: 784 kJ/mol; and K: 418 kJ/mol

Identify which pair of species below are isoelectronic

Kr and Br−1

Which of the following would be expected to have the lowest first ionization energy? (F, Li, O, C, Ne)

Li

Which one of the following isoelectronic ions would be expected to have the largest radius? (Cl-. Ca2+. K+. S2-. Sc3+)

S2-

Rank the following species by radius, from largest to smallest: Cl−, K+, Ca2+, Ar, S2−.

S2−, Cl−, Ar, K+, Ca2+

Which ion has the smaller radius? (Sn4+. Sn2+)

Sn4+

Which of the following has the smallest atomic radius? (S, P, Cl, Al, Si)

Cl

In the Mg+ ion, what are the effective nuclear charges experienced by a 1s electron and a valence electron, respectively?

+12; +2

In the neutral Al atom, what are the effective nuclear charges for a 1s electron and a valence electron, respectively?

+13; +3

What are the effective nuclear charges for a strontium atom valence electron and an n = 2 electron, respectively?

+2; +36

Which neutral atom has the smallest size? (Be, F, B, O, Li)

F

From the data below Element First Ionization Energy 1 - 1310 kJ/mol 2 - 1011 kJ/mol 3 - 418 kJ/mol 4- 2080 kJ/mol 5- 947 kJ/mol which elements are likely to be nonmetals?

1 & 4 only

Arrange the following ions in order of increasing radius: K+, Li+, Be2+, Na+.

Be2+ < Li+ < Na+ < K+

Consider the atoms A) arsenic B) nitrogen C) bismuth Arrange them in order of increasing first ionization energy.

C, A, B

F- is bigger than F because

F− has one more electron which causes greater electron repulsions in the outer orbitals, thus expanding the electron cloud.

Rank the following atoms and ions Li+, Be2+, He, H−, B3+ in order of decreasing size

H−, He, Li+, Be2+, B3+

What is the primary reason that atomic radius decreases as you move from left to right across the periodic table even though the number of electrons is increasing?

Increasing effective nuclear charge more strongly attracts the outermost electrons so the atoms get smaller

Rank the following in terms of decreasing ionic radii. (Na+, Mg2+, O2-, N3-, F-)

N3−, O2−, F−, Na+, Mg2+

The ions Na+, F−, and O2− each have ten electrons. What would be the order of the sizes of these three ions?

Na+ is smaller than F− which is smallerthan O2−.

Rank the following atoms in terms of decreasing atomic radius. (F, O, N, Mg, Na)

Na, Mg, N, O, F

Which of the following would be expected to have the highest first ionization energy? (Li, C, F, Ne, O)

Ne

Why is it harder to remove an electron from fluorine than from carbon, or, to put it another way, why are the valence electrons of fluorine more strongly bound than those of carbon?

The valence electrons of both fluorine and carbon are found at about the same distance from their respective nuclei but the greater positive charge of the fluorine nucleus attracts its valence electrons more strongly

Let X be a hypothetical element. Which of the following would be largest? (X2+. X+, X-. X2-, X)

X2-

The alkali metals have a low first and a high second ionization potential. The alkaline earth metals have low values for both first and second potentials. These observations suggest that

alkali metals should form stable +1 ions, while alkaline earth metals should form stable +2 ions.

In general, ionization energy tends to increase in the periodic table

from bottom to top and from left to right.

Which atom is smaller? (tin, germanium)

germanium

The element selenium (Se)

has a larger radius than sulfur

In general first ionization energy

increases from left to right across a period

The energy needed to remove electrons from an atom is called

ionization energy

As an atom's radius increases

its ionization energy decreases

As an atom's radius decreases,

its ionization energy increases

What is the order of increasing atomic radius? (phosphorus, antimony, bismuth)

phosphorus, antimony, bismuth

Atoms with which of the following outermost electrons should have rather low ionization energies? (p6, s1p1, s2, s1, s2p6)

s1

Which of the following concepts best describes the reason that atoms are larger and electron energies are weaker as you go down the periodic table?

shielding

Cl: 1255 kJ/mol; Ge: 784 kJ/mol; and K:418 kJ/mol (oxygen, selenium, tellurium)

tellurium, selenium, oxygen