Question 1

Which statement best describes the Greek model of the atom?

Accepted Answer

Atoms are indivisible, indestructible particles that make up all matter.

Question 2

Which of the following is NOT a statement from Dalton’s atomic theory?

Accepted Answer

Atoms can be created or destroyed in chemical reactions.

Question 3

What are the mass and charge of a neutron?

Accepted Answer

Mass: approximately $$1\ \mathrm{amu}$$, Charge: $$0$$

Question 4

Which model of the atom is described as a sphere of positive charge with electrons embedded throughout?

Accepted Answer

Thomson's plum pudding model

Question 5

Which of the following best defines radioactivity?

Accepted Answer

The spontaneous emission of particles or energy from unstable atomic nuclei.

Question 6

According to Rutherford’s nuclear model, where is most of the mass of an atom located?

Accepted Answer

In the nucleus

Question 7

How do positively charged particles behave when placed near a positive plate in an electric field?

Accepted Answer

They are repelled by the positive plate.

Question 8

Given the notation $$^{23}_{11}\mathrm{Na}^{+}$$, how many electrons does this ion have?

Accepted Answer

$$10$$

Question 9

Which of the following best defines an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 10

What is the atomic mass unit (amu) based on?

Accepted Answer

One-twelfth the mass of a carbon-12 atom.

Question 11

If chlorine has two isotopes, $$^{35}\mathrm{Cl} (75$$%) and $$^{37}\mathrm{Cl} (25$$%), what is the average atomic mass of chlorine?

Accepted Answer

$$35.5$$

Question 12

Which of the following best describes a line spectrum?

Accepted Answer

A series of discrete wavelengths emitted by excited atoms.

Question 13

According to the Bohr model, why do hydrogen atoms emit light at specific wavelengths?

Accepted Answer

Electrons transition between quantized energy levels, emitting photons of specific energies.

Question 14

Why was the Bohr model of the atom eventually replaced?

Accepted Answer

It could not explain the spectra of atoms with more than one electron.

Question 15

Which statement best describes an orbital in the quantum mechanical model?

Accepted Answer

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

Question 16

What information is provided by the principal quantum number ($$n) $$and the angular momentum quantum number ($$l$$)?

Accepted Answer

$$n$$ indicates the energy level; $$l$$ indicates the shape of the orbital.

Question 17

Which of the following is the correct symbol for an element with 17 protons?

Accepted Answer

$$\mathrm{Cl}$$

Question 18

What is the atomic mass of the carbon-12 isotope ($$^{12}\mathrm{C}$$)?

Accepted Answer

$$12\ \mathrm{amu}$$

Question 19

Which of the following best defines a subshell?

Accepted Answer

A set of orbitals with the same energy and shape within a principal energy level.

Question 20

Which of the following best describes an electron transition?

Accepted Answer

The movement of an electron from one energy level to another.

Introduction to Chemistry: Atomic Structure and Models Study Guide

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