Chapter 1 Vocabulary

Question 1

Average mass of an atom of an element; its unit of measure is the atomic mass unit (u), which is 1/12 the mass of a carbon-12 atom.

Answer 1

atomic mass

Question 2

Number of protons in the nucleus of each atom of a given element; is the top number in the periodic table.

Answer 2

atomic number

Question 3

A substance produced when elements combine and whose properties are different from each of the elements in it.

Answer 3

compound

Question 4

Negatively-charged particle that exists in an electron cloud formation around an atom’s nucleus.

Answer 4

electron

Question 5

Region surrounding the nucleus of an atom, where electrons are most likely to be found.

Answer 5

electron cloud

Question 6

Substance that cannot be broken down into simpler substances.

Answer 6

element

Question 7

Two or more atoms of the same element that have different numbers of neutrons in their nuclei.

Answer 7

isotope

Question 8

Sum of the number of protons and neutrons in the nucleus of an atom.

Answer 8

mass number

Question 9

Element that is malleable, ductile, a good conductor of electricity, and generally has a shiny or metallic luster.

Answer 9

metal

Question 10

Element that shares some properties with both metals and nonmetals.

Answer 10

metalloid

Question 11

A combination of compounds and elements that has not formed a new substance and whose proportions can be changed without changing the mixtures identity.

Answer 11

mixture

Question 12

Electrically-neutral particle that has the same mass as a proton and is found in an atom’s nucleus.

Answer 12

neutron

Question 13

Element that is usually a gas or brittle solid at room temperature and is a poor conductor of heat and electricity.

Answer 13

nonmetal

Question 14

Positively-charged particle in the nucleus of an atom.

Answer 14

proton

Question 15

Matter that has the same composition and properties throughout.

Answer 15

substance