Key Terms 4 & 5

Question 0

Nucleus

Answer 0

In physical science, an atoms central region, which is made up of protons and nuetrons

Question 1

Electron

Answer 1

A subatomic particle that has a negative charge

Question 2

Proton

Answer 2

A subatomic particle that has a positive charge and that is located in the nucleus of an atom; the number of protons in the nucleus is the atomic number, which determines the identity of an element

Question 3

Neutron

Answer 3

A subatomic particle that has no change and that is located in the nucleus of an atom

Question 4

Atomic number

Answer 4

The number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element

Question 5

Mass number

Answer 5

The sum of all the numbers of protons and nuetrons

Question 6

Isotope

Answer 6

An atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons

Question 7

Unified atomic mass unit

Answer 7

A unit of mass that describes the mass of an atom or molecule

Question 8

Mole

Answer 8

The SI base unit used to measure the amount of a substance whose number of particles is the same as the number of atoms of carbon is exactly 12 g of carbon-12

Question 9

Orbital

Answer 9

A region in an atom where there is a high probability of finding electrons

Question 10

Valence electrons

Answer 10

An electron that is found in the outermost shell of an atom that determines the atom’s chemical properties

Question 11

Photon

Answer 11

A unit or quantum of light; a particle of electromagnetic radiation that has zero rest mass and carries a quantum of energy

Question 12

Periodic law

Answer 12

The law that states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements

Question 13

Period

Answer 13

In chemistry, a horizontal row of elements in the periodic table

Question 14

Group

Answer 14

A vertical column of elements in the periodic table; elements in q group share chemical properties

Question 15

Ion

Answer 15

An atom, radical, or molecule that has gained or lost one or more electrons and has a negative or positive charge

Question 16

Metal

Answer 16

An element that is shiny and that conducts heat and electricity well

Question 17

Nonmetal

Answer 17

An element that conducts heat and electricity poorly and that does not form positive ions in an electrolytic solution

Question 18

Semiconductor

Answer 18

An element or compound that conducts electric current better than an insulator does but not as well as a conductor

Question 19

Alkali metal

Answer 19

One of the elements of the Group 1 of the periodic table (not hydrogen)

Question 20

Alkaline-earth metal

Answer 20

One of the elements of Group 2 of the periodic table

Question 21

Transition metal

Answer 21

One of the metals that can use the inner shell before the outer shell to bond

Question 22

Noble gas

Answer 22

One of the elements of Group 18 of the periodic table; unreactive

Question 23

Halogen

Answer 23

One of the elements of Group 17 of the periodic table; combine with metals to form salts