Question 1

Which scientist is credited with arranging the periodic table by increasing atomic number, leading to the modern periodic law?

Accepted Answer

Henry Moseley

Question 2

What is the electron configuration for a neutral magnesium atom ($$Z = 12$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$

Question 3

Which of the following best describes the periodic law?

Accepted Answer

Elements with similar properties recur at regular intervals when arranged by increasing atomic number.

Question 4

Which group of elements is most likely to form $$2+$$ cations?

Accepted Answer

Group 2A (alkaline earth metals)

Question 5

What is the noble gas configuration for bromine ($$Z = 35$$)?

Accepted Answer

$$[Ar]\ 4s^2$\ 3d$$^{10}$$\ 4p^5$

Question 6

Which principle states that electrons fill the lowest energy orbitals first?

Accepted Answer

Aufbau Principle

Question 7

A neutral sodium atom ($$Z = 11) $$loses one electron to form $$Na^+. $$What is the electron configuration of $$Na^+$$?

Accepted Answer

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

Question 8

Which of the following elements is a metalloid?

Accepted Answer

Silicon (Si)

Question 9

Which of the following ions is isoelectronic with neon ($$Ne$$)?

Accepted Answer

$$F^-$$

Question 10

Which of the following statements about transition metal cations is correct?

Accepted Answer

Electrons are removed from the $$s$$ orbital before the $$d$$ orbital when forming cations.

Question 11

Which of the following best explains why elements in the same group have similar chemical properties?

Accepted Answer

They have the same number of valence electrons.

Question 12

What is the correct electron configuration for $$Fe^{2+} ($$iron(II) ion, $$Z = 26$$)?

Accepted Answer

$$[Ar]\ 3d^6$

Question 13

Which of the following is the correct order of filling for the first four energy levels according to the Aufbau principle?

Accepted Answer

$$1s \rightarrow 2s \rightarrow 2p \rightarrow 3s$$

Question 14

Which of the following elements is most likely to gain one electron to achieve a noble gas configuration?

Accepted Answer

Chlorine (Cl)

Question 15

Which of the following best describes the metallic character trend in the periodic table?

Accepted Answer

Metallic character increases from top to bottom within a group.

Question 16

Which of the following is the correct noble gas configuration for silicon ($$Z = 14$$)?

Accepted Answer

$$[Ne]\ 3s^2$\ 3p^2$

Question 17

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

Accepted Answer

$$Cl^-$$

Question 18

Which rule states that electrons will fill degenerate orbitals singly before pairing up?

Accepted Answer

Hund's Rule

Question 19

Which of the following best describes the electron configuration of a fluoride ion ($$F^-$$, $$Z = 9$$)?

Accepted Answer

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

Question 20

Which of the following is a property of nonmetals?

Accepted Answer

Brittle when solid

The Periodic Table and Periodic Properties: Structure, Electron Configurations, and Trends

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