Question 1

Which statement best describes the Bohr model of the atom?

Accepted Answer

Electrons occupy fixed orbits around the nucleus, each with a specific energy.

Question 2

In the Bohr model, what is an 'orbit' and why is it necessary?

Accepted Answer

An orbit is a fixed path around the nucleus where electrons travel with defined energy, preventing them from spiraling into the nucleus.

Question 3

Which of the following best describes the Quantum-Mechanical model of the atom?

Accepted Answer

Electrons are found in orbitals, which are regions of space with a high probability of finding an electron.

Question 4

How do Bohr orbits differ from Quantum-Mechanical orbitals?

Accepted Answer

Bohr orbits are fixed paths with defined energies, while Quantum-Mechanical orbitals are regions where electrons are likely to be found.

Question 5

What does the principal quantum number $$n$$ describe in the Quantum-Mechanical model?

Accepted Answer

The energy level or shell of an electron in an atom.

Question 6

How many orbitals are in a $$p$$ subshell?

Accepted Answer

$$3$$

Question 7

Which of the following is the correct electron configuration for a neutral oxygen atom ($$Z=8$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^4$$

Question 8

According to Hund’s rule, how are electrons arranged in a set of degenerate orbitals (such as $$p$$ orbitals)?

Accepted Answer

Electrons fill all orbitals singly with parallel spins before pairing.

Question 9

Which principle states that no two electrons in an atom can have the same set of four quantum numbers?

Accepted Answer

Pauli exclusion principle

Question 10

Which orbital is always filled first in the ground state electron configuration of all elements?

Accepted Answer

$$1s$$

Question 11

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

Accepted Answer

Atomic size increases.

Question 12

Which of the following elements has the highest ionization energy?

Accepted Answer

Neon ($$Ne)$$

Question 13

What is the periodic trend for metallic character across a period from left to right?

Accepted Answer

Metallic character decreases.

Question 14

Which of the following is a correct noble gas shorthand electron configuration for calcium ($$Z=20$$)?

Accepted Answer

$$[Ar]\ 4s^2$

Question 15

How many valence electrons does phosphorus ($$P$$, $$Z=15) $$have?

Accepted Answer

$$5$$

Question 16

Which of the following best describes an orbital?

Accepted Answer

A region in space where there is a high probability of finding an electron.

Question 17

What is the correct order of filling for the following orbitals in a multielectron atom?

Accepted Answer

$$1s \rightarrow 2s \rightarrow 2p \rightarrow 3s \rightarrow 3p \rightarrow 4s \rightarrow 3d$$

Question 18

Which of the following ions has the same electron configuration as neon ($$Ne$$)?

Accepted Answer

$$Na^+$$

Question 19

Which quantum number describes the shape of an orbital?

Accepted Answer

Angular momentum quantum number ($$l)$$

Chapter 9: Atomic Structure, Electron Configuration, and Periodic Trends

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