Chemistry Midterm Set 2

Front 1

Cathode Rays

Back 1

Streams of electrons emitted by the cathode in a partially evacuated tube

Front 2

Electron

Back 2

A subatomic particle that has a negative charge and essentially zero mass

Front 3

Radioactivity

Back 3

The spontaneous emission of high-energy radiation and particles by materials

Front 4

Beta (β) Particle

Back 4

A radioactive emission that is a high-energy electron

Front 5

Alpha (α) Particle

Back 5

A radioactive emission with a charge of 2+ and a mass equivalent to that of a helium nucleus

Front 6

Nucleus

Back 6

The positively charged center of an atom that contains nearly all of the atom's mass

Front 7

Proton

Back 7

A positively charged subatomic particle present in the nucleus of an atom

Front 8

Neutron

Back 8

An electrically neutral subatomic particle found in the nucleus of an atom

Front 9

Atomic Mass Unit/Dalton

Back 9

Unit used to express the relative masses of atoms and subatomic particles; it is exactly 1/12 the mass of one atom of carbon with 6 protons and 6 neutrons in its nucleus

Front 10

Ion

Back 10

An atom or group of atoms that has a net positive or negative charge

Front 11

Isotopes

Back 11

Atoms of an element containing different numbers of neutrons

Front 12

Nuclide

Back 12

The nucleus of a specific isotope of an element

Front 13

Atomic Number (Z)

Back 13

The number of protons in the nucleus of an atom

Front 14

Nucleon

Back 14

Either a proton or a neutron in a nucleus

Front 15

Mass Number (A)

Back 15

The number of nucleons in an atom

Front 16

Periodic Table of the Elements

Back 16

A chart of the elements in order of their atomic numbers and in a pattern based on their physical and chemical properties

Front 17

Formula for Average Atomic Mass

Back 17

Let abundance = a, mass = m, element = X

mX = a1m1 + a2m2 + a3m3 (...)

Front 18

Average Atomic Mass

Back 18

A weighted average of masses of all isotopes of an element, calculated by multiplying the natural abundance of each isotope by its mass in amu and then summing these products

Front 19

Natural Abundance

Back 19

The proportion of a particular isotope, usually expressed as a percentage, relative to all the isotopes of that element in a natural sample

Front 20

Period

Back 20

A horizontal row in the periodic table

Front 21

Group/Family

Back 21

All elements in the same column of the periodic table

Front 22

Halogens

Back 22

The elements in group 17 of the periodic table, derived from Greek "salt former"

Front 23

Alkali Metals

Back 23

The elements in group 1 of the periodic table

Front 24

Alkaline Earth Metals

Back 24

The elements in group 2 of the periodic table

Front 25

Metals

Back 25

The elements on the left side of the periodic table that are typically shiny solids that conduct heat and electricity well and are malleable and ductile

Front 26

Nonmetals

Back 26

Elements with properties opposite those of metals, including poor conductivity of heat and electricity

Front 27

Metalloids/Semimetals

Back 27

Elements along the border between metals and nonmetals in the periodic table; they have some metallic and some nonmetallic properties

Front 28

Main Group Elements

Back 28

The elements in groups 1, 2, and 13-18 of the periodic table

Front 29

Transition Metals

Back 29

The elements in groups 3-12 of the periodic table

Front 30

Noble Gases

Back 30

The elements in group 18 of the periodic table

Front 31

Dalton's Law of Multiple Proportions

Back 31

The ratio of the two masses of one element that react with a given mass of another element to form two different compounds is the ratio of two small whole numbers (SO2 & SO3 >> 2:3; Basically means that you can't have half of an atom)

Front 32

Molecular Compound

Back 32

A compound composed of atoms held together in molecules by covalent bonds

Front 33

Covalent Bond

Back 33

A bond between two atoms created by sharing one or more pairs of electrons

Front 34

Molecular Formula

Back 34

A notation showing the number and type of atoms present in one molecule of a molecular compound

Front 35

Ionic Compound

Back 35

A compound composed of positively and negatively charged ions held together by electrostatic attraction

Front 36

Nonmetal Oxide

Back 36

An compound composed of oxygen and a nonmetal

Front 37

Ionic Compound

Back 37

A compound consisting of a metallic element and a nonmetal

Front 38

Explain how an ionic compound forms

Back 38

Each atom of he metal loses one or more electrons, forming a positively charged cation.

Each atom of the nonmetal loses one or more electrons, forming a negatively charged anion.

Front 39

Monatomic Ion

Back 39

An ion consisting of a single atom

Front 40

Cation

Back 40

A positively charged particle created when an atom or molecule loses one or more electrons

Front 41

Anion

Back 41

A negatively charged particle created when an atom or molecule gains one or more electrons

Front 42

Empirical Formula

Back 42

A formula showing the smallest whole-number ratio of elements in a compound

Front 43

Formula Unit

Back 43

The smallest electrically neutral unit of an ionic compound

Front 44

Polyatomic Ions

Back 44

Charged groups of two or more atoms joined together by covalent bonds

Front 45

Oxoanions

Back 45

Polyatomic ions that contain oxygen in combination with one or more other elements

Front 46

Acids

Back 46

Compounds that release hydrogen ions (H+) when dissolved in water; their chemical formulas begin with H

Front 47

Oxoacid

Back 47

An acid of an oxoanion