Chapter 2 Biol 1100

The innermost electron shell of an atom can hold up to​ _____ electrons.

• 18

• 32

• 1

• 2

• 8

Which of these relationships is true of an uncharged​ atom?

• The number of neutrons is equal to the number of protons.

• The number of electrons is equal to the number of neutrons.

• The number of protons is equal to the number of electrons.

• The atomic mass is equal to the number of electrons

• The atomic mass is equal to the atomic number.

What determines the types of chemical reactions that an atom participates​ in?

• its atomic number

• the number of protons it contains

• the number of electrons in the outermost electron shell

• its atomic mass

• the number of electrons in the innermost electron shell

What is the atomic number of an atom that has 6​ protons, 6​ neutrons, and 6​ electrons?

• 6

• 18

• 12

• 0

• -1

Which of these refers to atoms with the same atomic number but different atomic​ masses?

• These atoms have different numbers of protons.

• These atoms have different numbers of electrons.

• These atoms are different elements.

• These atoms are isotopes.

• These atoms are isomers.

  
  

​Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine​ have?

• 9

• 81

• 28

• 19

• 10

An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many protons does boron​ have?

• 0

• 5

• 11

• 16

• 6

Atoms are described by an atomic number and a mass number. The atomic number is the number of protons in the nucleus. The mass number represents the sum of the protons and the neutrons in the nucleus. If the number of negative electrons is equal to the number of positive​ protons, then the atom is neutral. If the number of protons and electrons are not​ equal, then the atom will have a charge.

For​ example, a phosphorus ion with 15​ protons, 17​ neutrons, and 18 electrons would have an atomic number of​ 15, a mass number of​ 32, and a charge of –3.

What is the mass number of an ion with 107 ​electrons, 157 ​neutrons, and a​ +1 charge?

(a)  

A substance that cannot be broken down into other substances by ordinary chemical procedures is​ a(n) __________.

• isotope

• proton

• compound

• molecule

• element

Which of the following subatomic particles always has a positive​ charge?

• proton

• atom

• element

• neutron

• electron