Review PS Mid-Term

2nd review, Devon is 1st semester

atomic number

number of protons above symbol

reactivity

The end of the periodic table are most reactive (increases)

valence electrons

As you move left to right across, the number of valence electrons increased by one excluding transition metals

Density

bottom elements are the most dense

electron shell diagram

When you go across a period the shell gets tighter because the nucleus gets stronger

noble gases

group 18, called inert because they rarely react to form compounds, all are gases at room temp

Alkali metals

group 1, shiny, good conductors of heat and electricity, react with/ water

Alkali earth metals

group 2

metals

normally solid, conduct heat and electricity, high melting points, ductile and malleable

non-metals

can be solids and gases, only Br is a liquid, brittle, poor conductors of heat and electricity

Metalliods

solid at room temp, some have metallic characteristics and some non-metals

Mass number

round atomic weight

Ionic bonds

electrons transferred

polyatomics

back of periodic table

covalent

electrons shared

Law of Conservation of Mass

Mass is neither destroyed or created in chemical reactions

Meter

Unit of length; 3.3

Solid

molecules that are tightly packed and retain their shape and size

Liquid

Molecules that bounce off of each other, can be compressed, and take the shape of their container.

Gas

Molecules that can move (slide) over each other and have a definite size (volume), but not shape and cannot be compressed.

Mixture

Something made up of two or more substances that can be separated by physical means

Compound

A substance made up of two or more atoms that must be separated by chemical means

Element

A substance that pure and made up of only one type of atom

Matter

Anything that has mass and takes up space

Heterogeneous

A mixture that is different through

Homogeneous

A mixture that is the same throughout

The nucleus of an atom is made of up

Protons and neutrons

The periodic table is organized by

Atomic number

The property of an element most responsible for its chemical properties

Protons

The electrons involved in chemical bonding we call

Valence electrons

atom

The smallest part of an element or a molecule, Building block of all things

Mass number

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

Compound.

Two or more elements combined

molecule

Two or more atoms are combined(can be same to atoms of the same element)