Question

name: _____________ pd: ____ chemistry u3l14_q2 ct module day 3 hw
4.
element | second ionization energy (kj/mol)
li | 7200
na | 4560
k | 3050
rb | 2630
the decrease in the second ionization energy of alkali metals going down the group, as shown in the table above, can be best attributed to a decrease in the coulombic force of attraction due to
(a) the removal of core electrons
(b) an increase in effective nuclear charge
(c) an increase in the average distance of the outermost electrons from the nucleus
(d) a decrease in electron - electron repulsion within the outermost shell
** 5. which of the following correctly compares the atomic radius of f to that of o and provides the best explanation?
(a) the atomic radius of f is larger than that of o because f has more occupied subshells than o does.
(b) the atomic radius of f is larger than that of o because f has more protons in the nucleus than o does.
(c) the atomic radius of f is smaller than that of o because f has a greater effective nuclear charge than o does.
(d) the atomic radius of f is smaller than that of o because valence electrons in f experience more shielding than those in o.
** 6.
graph: binding energy (mj/mol) on x - axis (500, 400, 300, 200), relative number of electrons on y - axis, two peaks labeled x (around 400) and another (around 300)
the photoelectron spectra of the 1s electrons of two isoelectronic species, $ca^{2 + }$ and ar, are shown above. which of the following correctly identifies the species associated with peak x and provides a valid justification?
(a) ar, because it has completely filled energy levels
(b) ar, because its radius is smaller than the radius of $ca^{2 + }$
(c) $ca^{2 + }$, because its nuclear mass is greater than that of ar
(d) $ca^{2 + }$, because its nucleus has two more protons than the nucleus of ar has

Explanation:

Step1: Analyze question 4

Alkali metals down group: atomic size increases, outermost electrons farther from nucleus. Coulombic attraction depends on distance.

Step2: Analyze question 5

F and O are in same period. F has more protons, higher effective nuclear charge, smaller radius.

Step3: Analyze question 6

Ca²⁺ and Ar are isoelectronic. Ca²⁺ has more protons, higher effective nuclear charge, higher binding energy for 1s electrons.

Answer:

1. C) an increase in the average distance of the outermost electrons from the nucleus
2. C) The atomic radius of F is smaller than that of O because F has a greater effective nuclear charge than O does.
3. D) Ca²⁺, because its nucleus has two more protons than the nucleus of Ar has