Year 9 Term 1 Flashcards
What is an atom made up of
Protons, neutrons, electrons, nucleus and electron shell
Atomic number
The number of protons the element has
Number of protons=
Number of electrons
Mass number
Number of protons+ number of neutrons
Number of neutrons=
Mass number- atomic number
Atoms of the same element have the same number of
protons
What is the overall charge of an atom
0 because the charge of the protons and electron cancel each other out and neutrons are neutral so that adds up to 0
isotopes
Atoms of the same element with a different number of neutrons (same number of protons and electrons)
First shell
Can only contain 2 electrons and has the lowest energy
Second shell
Can contain up to 8 electrons
Third shell
Can also contain up to 8 electrons
The last shell
Contains the remaining 3 or however many is left. Can contain more
Group number
Number of outer shells. Last digit on configuration
Period number
Number of shells. Number of digits in electronic configuration
The order of the elements
In order of atomic number low-high
The electronic structure of the elements
Each element has one more electron than the previous. The shells increase each time
Metals and non-metals
A line separates the two. Looks like stairs. Metals on left, non-metals on the right
Group 0- the noble gases
Elements are all non-metals. All elements have full outer shell. Don’t react with anything. They don’t need to gain or lose an electron. All react chemically in a similar way.
Group 1 reactivity
They get more reactive the further down you go because they have more electrons.
- more shells
- greater distance between nucleus and outer shell
- weaker attraction so easier to lose and electron
Properties of group 1 metals
Low density (all under 2g/cm3 Density increases as you go down the metals Some float on water m. point + b. point decrease as the reactivity decreases Group 1 salts are all white
Properties of transition metal
High density (all over 7g/cm3 Density increases as you go down the metals None float on water m. point + b.point decreases an you go down the table Transition metal salts are multi-coloured
Properties of group 7 (halogen)
Each element is made up of 2 of the same atom bonded together
Melting and boiling point increase as you go down
Very early periodic table
Lots of elements hadn’t been discovered
No transition metals
No Nobel gases
Early periodic table
More accurate atomic weights
No Nobel gases
Increased number of elements
More obvious period
