Basics of Chemistry

Matter is …

anything with mass

Matter can be classified into…

Pure: elements, compounds

Mixture: homogeneous, heterogenous

An element is…

made up of 1 type of atom

Compounds are…

made up of 1 or more different elements

Homogeneous mixtures…

are a blend of different chemicals but appear to be uniform to the naked eye

Heterogenous mixtures are..

not uniform and visibly different

In the modern periodic table, elements are arranged by…

atomic number

A period in a periodic table represents…

a row

A group in the periodic table represents…

A column

A valence shell is

the outermost shell of an atom

Valence electrons are

electrons on the valence shell

A period number refers to

the number of shells and atom has

There are 3 types of elements. They are

metals, non-metals, and metalloids.

Metals are

solid(ex mercury), ductile, malleable, shiny, good conductors, and silver ish

Non-metals are

brittle, dull, poor conductors, solid or gas(ex bromine)

Metalloids are

solid, shiny, brittle, good conductors of electricity but bad conductors of heat

All matter is made up of

atoms

Atoms are made up of 3 sub-atomic particles. They are

protons- positive charge, mass=1

neutrons- no charge, mass=1

electrons- negative charge, mass=1/2000

The atomic number shows

the number of protons

The number of protons and electrons are _______ in a neutral atom

equal

To find the number of neutrons,

subtract the atomic number from the atomic mass

There are 6 chemical families. They are

alkali metals, alkaline earth metals, transition metals, halogens, noble gases, and hydrogen

Alkali metals are

the first group of the periodic tables

Malleable, low density, low melting point, very reactive, silver or grey

They are especially reactive with water and form hydrogen gas and oxides

Alkaline earth metals are

the second group of the periodic table

somewhat malleable, high density, high melting point

used in fireworks and construction materials

Transition metals are

groups 3-12 of the periodic table

dense, durable, high melting points, very good conductors, solid

They are particularly precious and valuable

Halogens are

group 17 of the periodic table

exist in all 3 states, very electronegative, very reactive

Nobel gases are

group 18 of the periodic table

colorless, odorless, non-flammable, non-reactive, stable

In atomic diagrams, there are certain limits to how many electrons you can put in each shell.

Shell 1: 2 electrons

Shell 2: 8 electrons

Shell 3: 8 electrons

A Bohr-Rutgerford diagram looks like

A lewis dot diagram

is only concerned with the valence electrons

Ions are

elements with empty spots in their valence shell

Atoms with empty valence shells are ______ and become _______ by _________ or _________ __________.

1) unstable

2) stable

3) giving away

4) taking in

5) electrons

Atoms with less than 4 missing spots ______ electrons and form _______.

1) give away

2) cations

Atoms with more than 4 empty spots ________ electrons and form ______.

1) take in

2) anions