4.17 Mass Number

An atom of mercury contains 120 neutrons in its nucleus and 80 electrons around it. It contains _____ protons in its nucleus and its atomic number is _____.

80, 80

The atomic weight for elements is first determined by John

Dalton

An oxygen atom has 8 protons and 8 neutrons. What is the mass number of this oxygen atom? ___

16

If the sulfur atom has a mass number of 32 and 16 protons, how many electrons and neutrons does it have?

16,16

A sodium atom has 11 protons and 12 neutrons. What is the mass number of this sodium atom? ___

23

The atomic number of an element is 22 while its mass number is 48. How many neutrons does the element have?

26

An aluminum atom has 13 protons and 14 neutrons. What is the mass number of this aluminum atom? ___

27

Which scientist determined some atomic weights in the early 1800's?

John Dalton

The number of neutrons is used to calculate the _____ number of an atom.

Mass

For chlorine, the number of neutrons is 17.

false

The atomic number is placed as a superscript of the chemical symbol.

false

The mass number of an atom is the sum total of its electrons and protons.

false

Atoms always have the same number of protons and electrons.

true

In a nuclear symbol, the mass number is placed as a superscript before the chemical symbol.

true

The original atomic weights is based on the comparison of hydrogen.

true

Sodium has an atomic number of 11 and a mass number of 23. Which of the following are the correct number of protons, neutrons, and electrons, respectively, in a neutral sodium atom?

11, 12, 11

A carbon atom has 6 protons and 6 neutrons. What is the mass number of this carbon atom? ___

12

A nitrogen atom has 7 protons and 7 neutrons. Which of the following is the correct mass number of this nitrogen atom?

14

You will need to obtain a periodic table. Given the atomic notation of 64/30 Zn, indicate the number of protons, neutrons and electrons respectively, in an atom of zinc.

30, 34, 30

A chlorine atom has 17 protons and 18 neutrons. What is the mass number of this chlorine atom? ___

35

The element krypton has an atomic number of 36 and a mass number of 84. How many neutrons in a krypton atom?

48

What is the mass number of a cobalt atom that has 27 protons and 30 neutrons?

57

The atomic notation for a particular atom of boron is 11/5B. The atomic number is ____, while the mass number is ____.

5; 11

A tin atom has an atomic number of 50 and a mass number of 118. How many neutrons are present in this atom?

68

The number of protons plus the number of neutrons is called the _____ of an atom.

mass number