This document provides an overview of elements, compounds, and chemical formulas. It discusses how elements are arranged on the periodic table and classified as metals and non-metals. Metals are described as shiny, good conductors or heat/electricity, and malleable, while non-metals are dull, poor conductors, and brittle. Compounds are formed when different types of atoms bond together into molecules. Chemical formulas represent the elements that make up compounds and use prefixes to indicate the number of each atom. Common compounds like water, sodium chloride, and calcium carbonate are presented along with their formulas.

1. Elements and Compounds
Chemistry - 7th Grade | The Oxford School,Azuero
Prepared by Teacher Irina Ruiz
Monday, July 11, 2016

2. • The elements are arranged in order of
increasing atomic number
• The horizontal rows are called periods
• The vertical columns are called groups
• Elements in the same group are similar to
each other
Hydrogen is a non-metal but it is often put
in the middle.
Notice that most elements are metals, rather
than non-metals.
Each element has its own chemical symbol,
made from letters. Remember that you will
only find elements in the periodic table and
never compounds.
1
2
3
4
5
6
7
Monday, July 11, 2016

3. METALS
Iron, magnesium and gold are examples of
metal elements. Metals have properties in
common. They are:
• shiny, especially when they are freshly cut
• good conductors of heat and electricity
• malleable (they can be bent and shaped
without breaking)
Most metals also have other properties in
common. They are:
• solid at room temperature, except mercury
• hard and strong
• they have a high density
• they are sonorous
Monday, July 11, 2016

4. NON-METALS
Oxygen, carbon, sulfur and chlorine are
examples of non-metal elements. Non-metals
have properties in common. They are:
• dull (not shiny)
• poor conductors of heat and electricity (they
are insulators)
• weak and brittle (they easily break or shatter
when solid)
Most non-metals also have these properties:
• they have a low density (they feel light for
their size)
• They are NOT sonorous (they do not make a
ringing sound when hit)
Monday, July 11, 2016

5. Compounds and Formulae!
Some atoms like to hangout with other atoms.
And others prefer to keep to themselves...
WATER MOLECULE
FORMULA
H2O
When a group of atoms hang out
together, it is called a MOLECULE !
WATER is a COMPOUND because their molecules are made of different
kinds of atoms: 1 oxygen atom bonded with 2 hydrogen atoms
Monday, July 11, 2016

6. BASIC RULES ON
NAMING COMPOUNDS
• If the compound contains a metal, the
name of the metal comes first.
• If the compound contains a non-metal,
the name of the non-metal is usually
changed:
➡ When two elements form a compound
the name often ends in ‘ide’
➡ When the third element is oxygen, the
compound often have names ending with
’ate’
sodium chloride
A compound of Calcium, Carbon and
Oxygen is called:
calcium carbonate
Monday, July 11, 2016

7. PREFIXES in Compounds
How many of each kind of atoms are bonded together?
• ‘Mon’ or ‘mono’ means ONE
• ‘Di’ means TWO
• ‘Tri’ means THREE
carbon dioxide
MOLECULE
carbon monoxide
MOLECULE
Monday, July 11, 2016

8. When hydroxides are dissolved in
water, they form solutions that can
neutralise acids.
• NaOH sodium hydroxide
• KOH potassium hydroxide
• LiOH lithium hydroxide
Hydroxides are alkalis!
ACIDS ALKALIS
Monday, July 11, 2016

9. FORMULA NAME OF THE COMPOUND
WHAT IS THIS COMPOUND
MADE FROM?
H2O water
two atoms of hydrogen
bonded with
one atom of oxygen
NaBr sodium bromide
SO2 sulfur dioxide
CaCO3 calcium carbonate
MgSO4
KOH
LiNO3
H2S
Monday, July 11, 2016