Chemistry Midterm Review

Question 1

Dalton’s (Billiard Ball) model of the atom was rejected because it was discovered that _______.

Accepted Answer

the atom could be divided.

Question 2

Identify the correct symbol for an atom having 11 protons; 12 neutrons; and 10 electrons.

Accepted Answer

23Na+1

Question 3

Identify the correct symbol for an atom having 38 protons; 50 neutrons; and 36 electrons.

Accepted Answer

88Sr+2

Question 4

Arsenic, As has atomic number 33 and mass number 75. It has

Accepted Answer

33 protons, 33 electrons, and 42 neutrons.

Question 5

Dalton incorporated the law of definite proportions into his atomic theory by asserting that...

Accepted Answer

atoms of the same elements are identical.

Question 6

Nickel-60 has an atomic number of 28. How many neutrons does the nickel atom have?

Accepted Answer

32

Question 7

A hydrogen isotope consists of 1 protons, 1 electrons, and 1 neutrons. Its mass number is

Accepted Answer

2

Question 8

An atom is electrically neutral because

Accepted Answer

the numbers of protons and electrons are equal.

Question 9

As the mass number of an element’s isotopes increases, the number of protons

Accepted Answer

remains the same.

Question 10

Find the numbers of protons neutrons and electron in 10Be+2.

Accepted Answer

4 Protons: 6 Neutrons: 2 Electrons

Question 11

Calculate the molar mass of H2O.

Accepted Answer

18.02 g/mol

Question 12

All atoms of the same element have the same

Accepted Answer

atomic number.

Question 13

An element’s atomic number is equal to its number of

Accepted Answer

protons.

Question 14

What is the percentage composition of CH4?

Accepted Answer

74.8% C, 25.2% H

Question 15

Identify the correct symbol for an atom having 35 protons; 45 neutrons; and 36 electrons.

Accepted Answer

80Br-1

Question 16

An aluminum isotope consists of 13 protons, 13 electrons, and 14 neutrons. Its mass number is

Accepted Answer

27

Question 17

Calcium has atomic number 20 and mass number 40. It has

Accepted Answer

20 protons, 20 electrons, and 20 neutrons.

Question 18

Find the numbers of protons neutrons and electron in 31P-3.

Accepted Answer

15 Protons: 16 Neutrons: 18 Electrons

Question 19

Identify the correct symbol for an atom having 38 protons; 50 neutrons; and 36 electrons.

Accepted Answer

88Sr+2

Question 20

The total number of protons and neutrons in the nucleus of an atom is its

Accepted Answer

mass number.

Question 21

Iron-56 has an atomic number of 26. How many neutrons does the iron atom have?

Accepted Answer

30

Question 22

Dalton incorporated the law of conservation of mass into his atomic theory by asserting that...

Accepted Answer

atoms are indivisible.

Question 23

What is the formula mass of magnesium chloride, MgCl2?

Accepted Answer

95.21 amu

Question 24

What is the molar mass of HCl?

Accepted Answer

36.46 g/mol

Question 25

Carbon-14 (atomic number 6), the radioactive nuclide used in dating fossils, has

Accepted Answer

8 neutrons.

Question 26

A carbon isotope consists of 6 protons, 6 electrons, and 8 neutrons. Its mass number is

Accepted Answer

14

Question 27

Isotopes are atoms of the same element that have different

Accepted Answer

mass numbers.

Question 28

Two different isotopes of an element have different

Accepted Answer

numbers of neutrons.

Question 29

Find the mass of 0.75 moles of Neon.

Accepted Answer

15.14 g Ne

Question 30

Chemical analysis shows: 37.01% C, 2.22% H, 18.5%N, 42.27% O. What is the empirical formula?

Accepted Answer

C7H5N3O6

Question 31

Chlorine has atomic number 17 and mass number 35. It has

Accepted Answer

17 protons, 17 electrons, and 18 neutrons.

Question 32

Which of these must be the same for all atoms on an element?

Accepted Answer

atomic number

Chemistry Midterm Review

Questions 32

Chemistry Midterm Review

Questions 32