Question

1. use the following chemical formulas (a-d) of the phosphorus tetramer (p₄) to best answer the questions below:

answer the following multiple choice questions by entering the answer letter (a-e) in the blue field.
d) which of the following ions is likely to have the smallest ionic radius?
a. n²+
b. n+
c. n
d. n²-
e. n³-
answer
e) which of the following would have the largest first ionization energy?
a. he
b. ne
c. ar
d. kr
e. xe
answer
f) which of the following is the correct empirical formula for c₆h₁₄o₂s₂?
a. chos
b. c₆h₁₄o₂s₂
c. c₂h₇os₂
d. c₃h₁₄os
e. c₃h₇os
answer

Explanation:

• a) Molecular formula shows the exact number of atoms in a molecule. \(P_4\) has 4 P atoms, so B is the molecular formula.
• b) Empirical formula is the simplest whole - number ratio of atoms. For \(P_4\), the ratio of P atoms is \(1:1\) (simplest ratio), so D (which is just P) is the empirical formula.
• c) Structural formulas show the arrangement of atoms. A and C show the arrangement of P atoms in \(P_4\) (A is a ball - and - stick model and C is a line - bond or skeletal structure of \(P_4\)), so A and C are structural formulas.
• d) For ions of the same element:
• Cations have smaller radii than the neutral atom, and anions have larger radii than the neutral atom.
• The more positive the charge of the cation, the smaller the radius. \(N^{2+}\) has a higher positive charge than \(N^{+}\). So \(N^{2+}\) (A) has the smallest ionic radius.
• e) Ionization energy decreases down a group. Among He, Ne, Ar, Kr, Xe (noble gases), He is at the top of the group. So He (A) has the largest first ionization energy.
• f) To find the empirical formula of \(C_6H_{14}O_2S_2\):
• Divide the sub - scripts by 2 (the greatest common divisor of 6, 14, 2, 2).
• \(C_{6\div2}H_{14\div2}O_{2\div2}S_{2\div2}=C_3H_7OS\). So E is the empirical formula.

Answer:

a) B
b) D
c) A, C
d) A
e) A
f) E