General Biology I - Campbell And Reece - Ch.2

Front 1

Element

Back 1

A substance that cannot be broken down to other substances by chemical reactions.

Front 2

Compound

Back 2

A substance consisting of two or more different elements combined in a fixed ratio.

Front 3

Trace Elements

Back 3

Elements required by an organism in only minute details.

Front 4

Atom

Back 4

The smallest unit of matter that still retains the properties of an element.

Front 5

Dalton

Back 5

A formula created to measure the mass of atoms, subatomic particles, and molecules. neutrons and protons have the mass of roughly on of these, each about 1.7 x 10 to the -24. Also it is the same as the atomic mass unit.

Front 6

Atomic Number

Back 6

The number of protons in an element.

Front 7

Mass Number

Back 7

The sum of protons plus neutrons in the nucleus of an atom.

Front 8

Atomic Mass

Back 8

The approximation of the total mass of an atom, expressed in Daltons.

Front 9

Isotopes

Back 9

Some atoms have more neutrons than other atoms of the same element and therefore have a greater mass. These different atomic forms are called ________.

Front 10

Radioactive Isotopes (H)

Back 10

These are present when the nucleus decays spontaneously, giving off particles and energy. When the decay leads to a change in the number of protons, it transforms the atom to an atom of a different element. (H)

Hint 10

Radioactive Carbon decays to form Nitrogen

Front 11

Energy

Back 11

Defined as the capacity to cause change.

Front 12

Potential Energy

Back 12

Energy that matter possesses because of it's location or structure.

Front 13

Energy Levels

Back 13

The different states of potential energy that electrons have in an atom.

Front 14

Electron Configuration

Back 14

The distribution of electrons in the atom's electron shells.

Front 15

Valence Electrons

Back 15

The outermost electron.

Front 16

Valence Shell

Back 16

The outermost electron shell.

Front 17

Unreactive

Back 17

An atom with a complete valence shell is called _________ and will not interact readily with other atoms it encounters.

Front 18

Inert

Back 18

Meaning chemically unreactive.

Front 19

Orbital

Back 19

The three-dimensional space where an electron is found 90% of the time.

Front 20

Chemical Bonds

Back 20

Atoms with incomplete valence shells can interact with certain other atoms in such a way that each partner completes it's valence shell. These interactions usually result in atoms staying close together, held by attractions called __________.

Front 21

Covalent Bonds

Back 21

The sharing of a pair of valence electrons by two atoms.

Front 22

Molecule

Back 22

Two or more atoms held together by covalent bonds.

Front 23

Single Bond (H)

Back 23

A pair of shared electrons. (H)

Hint 23

H--H

Front 24

Structural Formula

Back 24

The notation, which represents two atoms and their bonding.

Front 25

Double Bond (H)

Back 25

A molecule sharing TWO pairs of valence electrons. (H)

Hint 25

C=C

Front 26

Valence

Back 26

The bonding capacity of an atom; usually equals the number of unpaired electrons in the atoms outermost shell.

Front 27

Electronegativity

Back 27

The attraction of a particular kind of atom for the electrons of a covalent bond.

Front 28

Nonpolar Covalent Bond

Back 28

A bond where electrons are shared equally.

Front 29

Polar Covalent Bond

Back 29

Where one atom is bonded to a more electronegative atom, the electrons of the bond are not shared equally.

Front 30

Ion

Back 30

A charged atom or molecule.

Front 31

Cation

Back 31

When the charge of an atom is positive.

Front 32

Anion

Back 32

When the charge of an atom is negative.