TCAP unit 2 review day 1

An element is a substance that is made
from one kind of atom only. It cannot
be broken down into simpler substances.

An element
An element

atom
atom

All atoms of an element are exactly the
same...the same number of protons,
neutrons, & electrons.

A compound is a substance that is made
from more than one element. The
different colors in the compounds below
represent different elements.

atom
atom

A compound made up of
2 different elements

A compound made up of
7 different elements

Each different colored

particle (atom) represents a

DIFFERENT ELEMENT that is part

of the compound in this model.

A compound made up of

3 different elements

Fe

An element’s chemical symbol is
written with either 1 capital
(uppercase) letter or 1 capital and
1 lowercase letter.

H

​OR

When two identical elements
combine,this is called an elemental
molecule.

H2 = Hydrogen

F2 = Fluorine

N2 = Nitrogen

Cl2 = Chlorine

O2 = Oxygen

H

H

N

N

O

O

F

F

Cl

Cl

When two identical atoms combine,this
is called an ELEMENTAL MOLECULE.
Because there are TWO of the same
atoms, it can also be called a
DIATOMIC MOLECULE (di = two)

H2 =Hydrogen

Cl2 = Chlorine

H

H

Cl

Cl

A chemical symbol represents a COMPOUND.

To determine whether something is an element or a

compound, all you have to do is count the capital

letters.

If there is more than one capital letter present,

it is a compound!

ELEMENT

Fe
B
Au
Ag
Hg
C

All have only

ONE CAPITAL LETTER

COMPOUND

FeO3
CH4

H2SO4
HNO3
CO2

C6H12O6

All have only MORE THAN

ONE CAPITAL LETTER

Both

Elements and Compounds

are

PURE SUBSTANCES

because they CANNOT be
broken down into anything
simpler and still remain the

same substance.