$$6.022 \times 10$$^{23}$$ particles/mol

A solution of $$\text{NaCl} in $$water

Question 1

Which experiment led to the discovery that atoms have a small, dense nucleus?

Accepted Answer

Rutherford's gold foil experiment

Question 2

What is the correct definition of atomic number ($$Z$$)?

Accepted Answer

The number of protons in the nucleus of an atom

Question 3

Which element is a chalcogen and is found in the 3rd period of the periodic table?

Accepted Answer

Sulfur (S)

Question 4

How many electrons are in a $$	ext{Fe}^{3+}$$ ion?

Accepted Answer

24

Question 5

Which of the following ions is a polyatomic ion?

Accepted Answer

$$	ext{SO}_4$$^{2-}$$

Question 6

What is Avogadro’s number and its units?

Accepted Answer

$$6.022 	imes 10$$^{23}$$ particles/mol

Question 7

Calculate the molar mass of $$	ext{Ca(NO}_3)_2.$$

Accepted Answer

$$164.10\ 	ext{g/mol}$$

Question 8

How many total atoms are in 1.0 g of $$	ext{CBr}_4$$? (Molar mass = $$235.8\ 	ext{g/mol})$$

Accepted Answer

$$9.1 	imes 10$$^{21}$$ atoms

Question 9

What is the empirical formula of a compound made from 2 g of hydrogen and 32 g of oxygen?

Accepted Answer

HO

Question 10

Which equation correctly relates energy, frequency, and Planck’s constant?

Accepted Answer

$$E = h
u$$

Question 11

Which type of electromagnetic radiation has the shortest wavelength?

Accepted Answer

Gamma rays

Question 12

In the Bohr model, what happens when an electron moves from $$n = 5 to$$ $$n = 7$$?

Accepted Answer

Excitation

Question 13

How many electrons can fit in a $$p$$ subshell?

Accepted Answer

6

Question 14

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

Accepted Answer

Aufbau principle

Question 15

What is the name of the compound $$	ext{CuSO}_4$$?

Accepted Answer

Copper(II) sulfate

Question 16

If a mineral has the formula $$	ext{K}_x	ext{SO}_3$$, what is the value of $$x$$?

Accepted Answer

2

Question 17

What is the mass percent of hydrogen in a compound made from 2.0 g of hydrogen and 16 g of oxygen?

Accepted Answer

11\%

Question 18

Which orbital shape is described as a sphere?

Accepted Answer

$$s$$ orbital

Question 19

What is the correct equation for the speed of light ($$c$$), wavelength ($$\lambda$$), and frequency ($$
u$$)?

Accepted Answer

$$c = \lambda
u$$

Question 20

Which of the following is a strong electrolyte solution?

Accepted Answer

A solution of $$	ext{NaCl} in $$water

Introductory Chemistry: Atomic Structure, Periodic Table, and Chemical Compounds

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