Question 1

Which of the following best explains why Mendeleev is credited with the development of the periodic table?

Accepted Answer

He used chemical properties to organize the table and predicted the properties of missing elements.

Question 2

Which equation correctly represents the effective nuclear charge ($$Z_{	ext{eff}}) $$experienced by a valence electron?

Accepted Answer

$$Z_{	ext{eff}} = Z - S$$

Question 3

Which trend is observed for the bonding atomic radius as you move across a period from left to right?

Accepted Answer

It decreases due to increasing effective nuclear charge.

Question 4

Why are cations smaller than their parent atoms?

Accepted Answer

Cations lose their outermost electron, reducing electron-electron repulsion.

Question 5

In an isoelectronic series, which ion would have the smallest radius?

Accepted Answer

$$	ext{Al}^{3+}$$

Question 6

Which of the following statements about ionization energy is correct?

Accepted Answer

Ionization energy increases across a period and decreases down a group.

Question 7

Why is the second ionization energy of sodium ($$	ext{Na}) $$much higher than the first?

Accepted Answer

The second electron is removed from a core shell, which is much closer to the nucleus.

Question 8

Which element would you expect to have the most negative electron affinity?

Accepted Answer

Fluorine ($$	ext{F})$$

Question 9

Which of the following best describes electronegativity?

Accepted Answer

The ability of an atom in a molecule to attract electrons to itself.

Question 10

Which bond is expected to be the most polar based on electronegativity differences?

Accepted Answer

HF

Question 11

Given the electron configurations below, why does oxygen have a lower first ionization energy than nitrogen?

Accepted Answer

Oxygen's added electron pairs up in a 2p orbital, increasing electron-electron repulsion.

Question 12

Which of the following equations correctly expresses the dipole moment ($$\mu) of a $$molecule?

Accepted Answer

$$\mu = Qr$$

Question 13

Which of the following elements would have the highest electronegativity?

Accepted Answer

Fluorine ($$	ext{F})$$

Question 14

Which of the following best explains why the electron affinity of noble gases is positive?

Accepted Answer

They have a full p sublevel, making the addition of an electron energetically unfavorable.

Question 15

Which of the following ions has the same electron configuration as neon ($$1s^2$$ $$2s^2$$ $$2p^6$$)?

Accepted Answer

$$	ext{Na}^+$$

Question 16

Which of the following statements about the periodic trend in atomic radius is correct?

Accepted Answer

Atomic radius decreases across a period due to increasing effective nuclear charge.

Question 17

A patient is exposed to a toxic ion that is isoelectronic with $$	ext{Ne}$$ but has a much smaller ionic radius. Which ion is most likely responsible?

Accepted Answer

$$	ext{Al}^{3+}$$

Question 18

Which of the following best describes the trend in first ionization energy for the s- and p-block elements?

Accepted Answer

It increases across a period and decreases down a group.

Question 19

Which of the following is a real-world application of electronegativity differences?

Accepted Answer

Determining the polarity of water, which is essential for its solvent properties in biological systems.

Question 20

Which of the following best explains why the bond in HF is more polar than the bond in HI?

Accepted Answer

The electronegativity difference between H and F is greater than that between H and I.

Periodic Properties of the Elements: Structured Study Notes for GOB Chemistry

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