Chemestry

Front 1

Mendeleev

Back 1

Credited with publication of the first periodic table

Front 2

Atom

Back 2

Smallest unit of an element that can exist without loss of identity

Front 3

Halogens

Back 3

Group VII elements with seven electrons in their valance shell

Front 4

Substance

Back 4

Matter that can be purified at the molecular level (all units have the same composition)

Front 5

Alkali metals

Back 5

Elements with one electron in their valence shell

Front 6

Isotope

Back 6

Two or more atoms with equal number protons but diff # of neutrons

Front 7

Neutron

Back 7

Atom particle with no charge

Front 8

Bohr

Back 8

Developed the planetary model of atomic structure

Front 9

Proton

Back 9

Positively charged particle located in the nucleus of an atom

Front 10

Mass number

Back 10

The sum of protons and neutrons in an atom

Front 11

Atomic mass

Back 11

Represents all the atoms of that element on planet earth

Front 12

Atomic number

Back 12

Equal to number of protons in the nucleus of an atom

Front 13

Group

Back 13

Verticle column of elements in the periodic table- a family of elements

Front 14

Periodic table

Back 14

Systematic arrangements of the elements based on the atomic number

Front 15

Valence shell

Back 15

Furthermost energy level in an atom that is occupied with electrons

Front 16

Period

Back 16

Horizontal row of elements in the periodic table

Front 17

Significant figures

Back 17

Digits expressed in a measurement quantity which convey its precission

Front 18

Distillation

Back 18

Purification technique employing first boiling a liquid and then condensation of vapor

Front 19

Precision

Back 19

Statment of how close several measured values are to each other

Front 20

Filtration

Back 20

Purification of a heterogeneous mixture by separation of solids from liquid

Front 21

Accuracy

Back 21

Statement of how close several measured values are to the true or acccepted value

Front 22

Molecular formula

Back 22

Combination ratio of atoms that represent the smallest recognizable unit of a molecular substance

Front 23

Measurement

Back 23

Comparison of an unknown quantity to a known reference standard

Front 24

Heterogenous mixture

Back 24

Composition of the matter varies

Front 25

Homogeneous mixture

Back 25

Composition is uniform throughout

Front 26

Density

Back 26

Mass per unit volume

Front 27

Conversion (or unit) factor

Back 27

Fraction where the numerator equals the denominator

Front 28

Units and precision

Back 28

Necessary components of a number for composition of a scientific measurements.

Front 29

Matter

Back 29

Everything in the universe that occupies space and had mass