Atomic theory 7 Flashcards
Define compound
A compound is a substance that is made up of two or more elements combined together chemically.
What must be present between the atoms to make the elements combine together?
Some type of attractive forces present between the atoms.
What is the name of the forces of attractions that are present between atoms?
Chemical bonds
Define an element
An element is defined as a substance that cannot be reduced to other simpler substances by chemical means or produced by combining simpler substances.
Who put forward the definition of an element and when?
Sir Robert Boyle, early 1900’s
Define the octet rule
This rule states that when atoms bond, most atoms tend to want an electron arrangement of eight electrons in their outermost shell (energy level).
Are there any exceptions to the octet rule?
Yes many
Do noble gases form chemical bonds with other atoms?
Not often
Why do noble gases not normally form chemical bonds with other atoms?
As they have eight electrons in their outermost energy level and hence are very stable on their own.
Do noble gases have full outer shells?
Yes
Define valency
The valency of an atom tells us the number of chemical bonds an atom can form.
What determines the valency?
The number of electrons in the outermost shell.
What will atoms do to attain a full ‘octet’?
Share, lose or gain electrons
Valency of group 1
1
Valency of group 2
2
Valency of group 3
3
Valency of group 4
4 (common)
Valency of group 5
3 (common)
Valency of group 6
2 (common)
Valency of group 7
1
Valency of group 8
0
What is the formula of magnesium chloride?
n
What is the formula of hydrogen sulphide?
n
What is the formula of aluminium oxide?
n
