Question 1

Which of the following best explains why alkali metals (Group 1A) form cations with a 1+ charge?

Accepted Answer

They have one more electron than the previous noble gas and tend to lose it to achieve noble gas configuration.

Question 2

A main-group element has an outer electron configuration of $$ns^2np^4$. What charge is likely for an ion of this element?

Accepted Answer

$$2-$$

Question 3

Which of the following statements about halogens is correct?

Accepted Answer

Halogens tend to gain one electron in reactions with metals, forming anions with a $$1-$$ charge.

Question 4

Which element is most likely to form a $$2+$$ cation based on its position in the periodic table?

Accepted Answer

Magnesium ($$Mg)$$

Question 5

What is the trend in atomic radius as you move down a group in the periodic table?

Accepted Answer

Atomic radius increases due to larger valence orbitals.

Question 6

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

Accepted Answer

$$Z_{eff} = Z - S$$, where $$Z is $$the nuclear charge and $$S is $$the number of electrons in lower energy levels.

Question 7

Which of the following ions is largest in size?

Accepted Answer

$$O^{2-}$$

Question 8

Why are cations generally smaller than their parent atoms?

Accepted Answer

Cations lose valence electrons, resulting in a smaller electron cloud and increased effective nuclear charge.

Question 9

Which of the following best explains the large jump in ionization energy between the third and fourth ionization energies for a second-row element?

Accepted Answer

The fourth electron is being removed from a core shell, which requires much more energy.

Question 10

Which of the following elements has the highest first ionization energy?

Accepted Answer

Neon ($$Ne)$$

Question 11

Which statement best explains why sodium commonly forms a $$1+$$ ion and not a $$2+$$ ion?

Accepted Answer

Sodium has only one valence electron that is easily removed; removing a second electron would be more difficult because it would be a core electron.

Question 12

Which of the following best describes the trend in metallic character across a period?

Accepted Answer

Metallic character decreases from left to right across a period.

Question 13

Which property is characteristic of metals?

Accepted Answer

Metals are malleable, ductile, and conduct electricity.

Question 14

Which of the following elements is most likely to have a large, negative electron affinity?

Accepted Answer

Chlorine ($$Cl)$$

Question 15

Which of the following statements about atomic radius is correct?

Accepted Answer

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

Question 16

Which of the following ions is isoelectronic with $$Ne$$?

Accepted Answer

$$F^{-}$$

Question 17

Which of the following best explains why valence electrons are more important than core electrons in determining the reactivity and bonding of atoms?

Accepted Answer

Valence electrons are most loosely held and are involved in bonding.

Question 18

Which of the following best describes the electron configuration of a $$Al^{3+}$$ ion?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^6$$

Question 19

Which of the following is true about the atomic radii of isotopes, such as $$^{12}C$$ and $$^{13}C$$?

Accepted Answer

$$^{12}C$$ and $$^{13}C$$ have the same atomic radius.

Periodic Properties of Elements: Study Notes

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