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science revision yr 8
- using the periodic
table to show
where metals and
non metals are
- All the different elements are
arranged in a chart called the
periodic table. A Russian
scientist called Dmitri
Mendeleev produced one of the
first practical periodic tables in
the 19th century. The modern
periodic table is based closely
on the ideas he used:
- Melting point Density Reactivity Lithium Decreases down the group Increases down the
group Increases down the group Sodium Decreases down the group Increases down the
group Increases down the group Potassium Decreases down the group Increases down the
group Increases down the group Rubidium Decreases down the group Increases down the
group Increases down the group
- Melting point Density Reactivity Lithium Decreases down the group Increases down the
group Increases down the group Sodium Decreases down the group Increases down the
group Increases down the group Potassium Decreases down the group Increases down the
group Increases down the group Rubidium Decreases down the group Increases down the
group Increases down the group
- The main groups are numbered from 1 to 7
going from left to right, and the last group on
the right is group 0. The section in the middle
of the table is called the Transition Metals.
You may also see all the groups numbered
(including the transition metals), this time
from 1 to 18. If you know what one of the
elements in a group is like, you can make
predictions about the other elements in a
group. For example, all the elements in group
1 are reactive metals, and all the elements in
group 0 are unreactive non-metals.
- The zig-zag line in this diagram
separates the metals, on the
left, from non-metals, on the
right. 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. So you won’t find
substances like water or copper
sulfate in the periodic table.
- All the different elements are
arranged in a chart called the
periodic table. A Russian
scientist called Dmitri
Mendeleev produced one of the
first practical periodic tables in
the 19th century. The modern
periodic table is based closely
on the ideas he used:
- 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
- Metals react with oxygen to produce compounds called metal oxides. For example, magnesium reacts
with oxygen to produce magnesium oxide. The reaction can be represented by this word equation:
magnesium + oxygen → magnesium oxide Metal oxides are bases. They react with acids and
neutralise them. Some metal oxides dissolve in water and, when they do, they produce alkaline
solutions. You can find out more about acids and alkalis in this Chemistry study
- non metals
- 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 NOTsonorous (they do not
make a ringing sound when hit) Eleven
non-metals are gases at room temperature,
including oxygen and chlorine. One
non-metal, bromine, is a liquid at room
temperature. The other non-metals are
solids at room temperature, including
carbon and sulfur.
- Reactions of non-metals Non-metals react
with oxygen to produce non-metal oxides.
For example, sulfur reacts with oxygen to
produce sulfur dioxide. The reaction can
be represented by this word equation:
sulfur + oxygen → sulfur dioxide
Non-metal oxides react with bases and
neutralise them. Some non-metal oxides
dissolve in water and, when they do, they
produce acidic solutions.
- 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 NOTsonorous (they do not
make a ringing sound when hit) Eleven
non-metals are gases at room temperature,
including oxygen and chlorine. One
non-metal, bromine, is a liquid at room
temperature. The other non-metals are
solids at room temperature, including
carbon and sulfur.
- Diamond and graphite Carbon is a solid non-metal element. Pure
carbon can exist in very different forms. The most common two
are diamond and graphite. The table shows some differences
between them. Diamond Graphite Transparent and
colourless Opaque and black Hard Soft Diamond is the hardest
natural substance on Earth, but it is also very brittle and will
shatter if hit with a hammer.
- Metals v non-metals Most elements are metals, rather than
non-metals. The table summarises some differences in their
properties. Properties Metals Non-metals
Appearance Shiny Dull State at room temperature Solid
(except mercury, which is a liquid) About half are solids, about
half are gases, and one (bromine) is a liquid Density High (they
feel heavy for their size) Low (they feel light for their size)
Strength Strong Weak Malleable or brittle Malleable (they bend
without breaking) Brittle (they break or shatter when
hammered) Conduction of heat Good Poor (they are insulators)
Conduction of electricity Good Poor (they are insulators, apart
from graphite) Magnetic material Only iron, cobalt and
nickel None Sound when hit They make a ringing sound (they
are sonorous) They make a dull sound Type of oxide Basic or
alkaline Acidic Telling them apart Notice that metals and
non-metals have opposite properties to each other. It is
usually easy to tell metals and non-metals apart, but some t
- 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
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