chemistry - matter Flashcards
what is an element
Element – Substance made of one type of atom, elements are listed on the periodic table
what is a compound
Compound – Substance made of more than one type of atom chemically joined together.
what is a chemical symbol
Chemical Symbol – The 1 or 2 letter symbol used for each element. The first letter is always upper case. The second letter, if there is one, is lower case. (e.g. H, Na, C, Mg, O, Cl)
what is a chemical formula
Chemical Formulae – The chemical symbols and numbers representing the atoms that make up a substance and how many of each. (e.g. CO2, H2O, MgO, O2, H2, Mg)
what is an element
An element is a substance that cannot be broken down into other substances.
come up with examples of elements
Some examples are
gold, silver, oxygen, chlorine and helium.
how many elements are naturally occuring
There 92 naturally occurring elements on earth and
scientists have made a few more.
what lists the elements
The Periodic Table lists the elements.
how are elements grouped
The elements with similar
properties are grouped together.
how do you identify an element
Every element has its own chemical symbol.
how do you write a chemical symbol
The first letter is
always a capital letter. If there is a second letter in the symbol, then it will be lower case e.g. C, O, Li and He
what is a vertical column called
A vertical column is called a group.
Acid
A solution with a pH value less than 7.
Alkali
A soluble base. A solution with a pH value greater than 7.
Alkali
Metals
Name for Group 1 of the periodic table. Highly reactive metals.
Base
A substance that neutralises an acid
Chemical
Property
How a substance behaves in its chemical reactions.
Density
How much mass there is per volume.
Density=Mass ÷ Volume
Displacement Reaction
In a displacement reaction a more reactive element displaces (or pushes out) a less reactive element from a compound.
Group
Column on the periodic table. Elements in same group have similar chemical properties.
Halogens
Name for Group 7 of the periodic table. Highly reactive non metals.
Metal
Elements on the left of the stepped-line of the periodic table. They are good conductors.
Metalloid
Elements near the stepped line of the periodic table. They show some properties of metals and some of non-metals.
Noble Gases
Name for Group 0 of the periodic table. Very unreactive gases.
Non-Metal
Elements on the right of the stepped-line of the periodic table. They are poor conductors.
Period
A row on the periodic table.
Physical
Property
A property of a material you can observe or measure. e.g. appearance, melting point, or conductivity.
Reactive
Something is reactive if it easily takes part in reactions without adding lots of energy.
Trend
A pattern in measurements or observations that changes gradually.
what is a horizontal row
a horizontal row is called a period.