The effective nuclear charge $$Z_{\text{eff}}$$ increases, attracting valence electrons more strongly.

Question 1

Which quantum number is introduced to describe the property of electron spin, and what are its possible values?

Accepted Answer

The spin quantum number $$m_s$$, with possible values $$+\frac{1}{2}$$ and $$-\frac{1}{2}$$

Question 2

Which of the following best explains why the atomic radius decreases across a period from left to right?

Accepted Answer

The effective nuclear charge $$Z_{	ext{eff}}$$ increases, attracting valence electrons more strongly.

Question 3

Which element would you expect to have the largest covalent radius based on the periodic trends?

Accepted Answer

Iodine ($$I)$$

Question 4

What is the correct electron configuration and orbital diagram for a nitrogen atom?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^3$$ with three unpaired electrons in the $$2p$$ orbitals

Question 5

Why does the first ionization energy generally increase across a period?

Accepted Answer

The effective nuclear charge increases, holding electrons more tightly.

Question 6

Which of the following best describes the trend in ionic radii for cations compared to their parent atoms?

Accepted Answer

Cations are smaller than their parent atoms because they lose electrons and experience a greater effective nuclear charge.

Question 7

Which of the following equations correctly represents the first ionization energy process for sodium?

Accepted Answer

$$\mathrm{Na}(g) \rightarrow \mathrm{Na}^+(g) + e^-$$

Question 8

Why is there a large jump in the third ionization energy of magnesium compared to the second?

Accepted Answer

The third electron is removed from a core shell, which is closer to the nucleus and more tightly bound.

Question 9

Which of the following best explains the exception in the first ionization energy trend between nitrogen and oxygen?

Accepted Answer

Nitrogen has a half-filled $$2p$$ sublevel, making it more stable and harder to ionize.

Question 10

Which of the following statements about electron affinity is correct?

Accepted Answer

A negative electron affinity value means energy is released when an electron is added.

Question 11

Which element would you expect to have the most negative electron affinity based on periodic trends?

Accepted Answer

Fluorine ($$F)$$

Question 12

Which of the following best describes the trend in atomic radius down a group in the periodic table?

Accepted Answer

Atomic radius increases due to the addition of energy levels.

Question 13

Which of the following best explains why anions are larger than their parent atoms?

Accepted Answer

Anions have gained electrons, increasing electron-electron repulsion and expanding the electron cloud.

Question 14

Which of the following is the correct order of increasing first ionization energy for the elements Na, Mg, and Al?

Accepted Answer

$$\mathrm{Na} \u003c \mathrm{Mg} \u003c \mathrm{Al}$$

Question 15

Which of the following best describes the concept of effective nuclear charge ($$Z_{	ext{eff}}$$)?

Accepted Answer

$$Z_{	ext{eff}} is $$the actual nuclear charge minus the shielding effect of inner electrons.

Question 16

A hospital is using sodium vapor lamps for lighting. Which property of sodium makes it easy to produce light in this way?

Accepted Answer

Sodium has a low first ionization energy, making it easy to remove electrons and produce light.

Question 17

Which of the following best explains why the removal of each successive electron from an atom requires more energy?

Accepted Answer

Each successive electron is removed from a lower energy level, which is closer to the nucleus and more tightly bound.

Question 18

Which of the following elements would you expect to have the highest metallic character?

Accepted Answer

Cesium ($$Cs)$$

Question 19

Which of the following best describes the relationship between atomic radius and effective nuclear charge ($$Z_{	ext{eff}}) $$across a period?

Accepted Answer

As $$Z_{	ext{eff}}$$ increases, atomic radius decreases.

Periodic Properties of Elements: Electron Spin, Atomic and Ionic Radii, Ionization Energy, and Electron Affinity

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