Question 1

Which of the following statements best describes the modern atomic theory?

Accepted Answer

All matter is composed of atoms, and atoms of different elements are unique.

Question 2

A neutral atom has 14 electrons and a mass number $$A = 30. $$What is the identity of this atom and how many neutrons does it have?

Accepted Answer

Silicon, 16 neutrons

Question 3

Which equation correctly relates the atomic number $$(Z)$$, mass number $$(A)$$, and number of neutrons $$(n) in an $$atom?

Accepted Answer

$$A = Z + n$$

Question 4

Copper has two naturally occurring isotopes: $$^{63}\mathrm{Cu} (69.09$$%, mass = 62.9298 amu) and $$^{65}\mathrm{Cu} (30.91$$%, mass = 64.9278 amu). What is the atomic mass of copper?

Accepted Answer

$$63.55\ \mathrm{amu}$$

Question 5

Which group on the periodic table contains elements that are shiny, soft metals with low melting points and react vigorously with water?

Accepted Answer

Group 1A (Alkali metals)

Question 6

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

Accepted Answer

They have the same number of valence electrons.

Question 7

What is the condensed electron configuration for zinc $$(Z = 30)$$?

Accepted Answer

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

Question 8

Which of the following statements about orbitals is correct?

Accepted Answer

Each orbital can hold a maximum of two electrons with opposite spins.

Question 9

Which element is a metalloid based on its position in the periodic table?

Accepted Answer

Silicon

Question 10

A sample of an unknown element is a colorless, odorless gas that does not react with other elements under normal conditions. To which group does this element most likely belong?

Accepted Answer

Group 8A (Noble gases)

Question 11

Which of the following electron configurations represents a halogen?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^5$$

Question 12

Which of the following best describes the relationship between wavelength and energy for electromagnetic radiation?

Accepted Answer

Shorter wavelength corresponds to higher energy.

Question 13

Which of the following is the correct electron-dot symbol for sulfur?

Accepted Answer

$$\cdot\!\!\cdot S \cdot\!\!\cdot$$

Question 14

Which of the following best explains why sodium metal must be stored under oil?

Accepted Answer

It reacts violently with water to form alkaline products.

Question 15

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

Accepted Answer

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

Question 16

Which of the following is a correct statement about isotopes?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 17

Which of the following elements is most likely to be found as a diatomic molecule in nature and is highly reactive?

Accepted Answer

Chlorine

Question 18

Which of the following best describes the quantum mechanical model of the atom?

Accepted Answer

Electrons are restricted to certain energy levels and locations, and their energies are quantized.

Question 19

Which of the following is the correct electron configuration for a neutral atom of phosphorus $$(Z = 15)$$?

Accepted Answer

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

Question 20

Which of the following best describes the trend in atomic radius across a period from left to right?

Accepted Answer

Atomic radius decreases due to increasing nuclear charge.

Atoms and the Periodic Table: Structured Study Notes for GOB Chemistry

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