Chemistry Unit 3 Exam

Question 1

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

Accepted Answer

2

Question 2

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

Accepted Answer

27

Question 3

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

Accepted Answer

88Sr+2

Question 4

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

Accepted Answer

14

Question 5

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

Accepted Answer

15 Protons: 16 Neutrons: 18 Electrons

Question 6

Calculate the molar mass of H2O.

Accepted Answer

18.02 g/mol

Question 7

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

Accepted Answer

protons.

Question 8

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

Accepted Answer

32

Question 9

Two different isotopes of an element have different

Accepted Answer

numbers of neutrons.

Question 10

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

Accepted Answer

atomic number

Question 11

Isotopes are atoms of the same element that have different

Accepted Answer

mass numbers.

Question 12

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

Accepted Answer

80Br-1

Question 13

All atoms of the same element have the same

Accepted Answer

atomic number.

Question 14

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

Accepted Answer

33 protons, 33 electrons, and 42 neutrons.

Question 15

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

Accepted Answer

20 protons, 20 electrons, and 20 neutrons.

Question 16

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

Accepted Answer

remains the same.

Question 17

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

Accepted Answer

17 protons, 17 electrons, and 18 neutrons.

Question 18

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

Accepted Answer

8 neutrons.

Question 19

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

Accepted Answer

mass number.

Question 20

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

Accepted Answer

atoms of the same elements are identical.

Question 21

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

Accepted Answer

the atom could be divided.

Question 22

Find the mass of 0.75 moles of Neon.

Accepted Answer

15.14 g Ne

Question 23

Scientist knew that Rutherford’s nuclear model of the atom was unstable because_______.

Accepted Answer

the electron would crash into the nucleus.

Question 24

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

Accepted Answer

15 Protons: 16 Neutrons: 18 Electrons

Question 25

What is the molar mass of HCl?

Accepted Answer

36.46 g/mol

Question 26

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

Accepted Answer

23Na+1

Question 27

An atom is electrically neutral because

Accepted Answer

the numbers of protons and electrons are equal.

Question 28

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

Accepted Answer

30

Question 29

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

Accepted Answer

4 Protons: 6 Neutrons: 2 Electrons

Question 30

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

Accepted Answer

atoms are indivisible.

Question 31

What is the formula mass of magnesium chloride, MgCl2?

Accepted Answer

95.21 amu

Question 32

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

Accepted Answer

88Sr+2

Chemistry Unit 3 Exam

Questions 32

Chemistry Unit 3 Exam

Questions 32