C9 - The periodic table Flashcards
Why is it called the periodic table
elements with similar properties occur at regular intervals and happen ‘periodically’
How is the periodic table structure
Elements in the same group (column) have the same number of electrons in their outer shell.
Elements in group 2 have 2 electrons in outer shell
Elements in group 3 and 3 electrons in outer shell and so on.
Rows are also called periods
Each new row an element has one more shell of 8 electrons.
Metals are the
left of the periodic table
Non-metals are on the
right of the periodic table
What is another name for the group 1 metals
alkali metals
Properties of group 1 metals
Reactivity increases as you go down the group
Soft to cut
Shiny
Very low MP compared to most metals. MP decreases going down the group
Low density
React easily with air and water
Why are group 1 metals so reactive
because they only have one electron in their outer shell which they want to give away when reacted with a non metal. The more electrons a metal atom has to lose the more energy needed to start the reaction. Therefore group 2 is less reactive than group 1 as they have to lose 2 electrons
Observations of different group 1 metals reacting with substances
When burned
Lithium - red
sodium - orange/yellow
potassium - lilac
In water metals react vigorously giving off lots of effervescence.
Lithium - fizzes steadily and floats becoming smaller until it disappears
Sodium - Fizzes rapidly and melts to form a ball on the water surface
Potassium - Ignites and creates a mini explosion
Chlorine:
React easily, burning in chlorine to form a white solid
word and symbol equation of group 1 metals reacted with different substances
lithium + oxygen ==> lithium oxide 4Li + O2 ==> 2Li2O lithium + water ==> lithium hydroxide + hydrogen 2Li + 2H2O ==> 2LiOH + H2 lithium + chlorine ==> lithium chloride 2Li + Cl2 ==> 2LiCl
Another name for group 7 metals
halogens
Properties of halogens
Exist as diatomic molecules (contain 2 atoms)
Reactivity decreases going down the group
7 electrons in outer most shell
Florine - pale yellow gas
Chlorine - pale green gas
Bromine - red-brown liquid
Iodine - black solid
Observations of different group 7 metals reacting with substances
Dissolved in water forming solutions behaving like bleach
Chlorine solution - pale yellow
Bromine solution - orange
Iodine solution - yellow/brown
Halogens form salts with metals
Displacement reactions:
More reactive halogen will displace a less reactive one from a solution of a salt.
word and symbol equation of group 7 metals reacted with different substances
chlorine + water ==> hydrochloric acid + chloric acid
Cl2 + H2O ==> HCI + HCIO
iron + chlorine ==> iron(III) chloride
2Fe + 3Cl2 ==> 2FeCl3
Chlorine + sodium bromide ==> sodium chloride + bromine
Cl2 + 2NaBr ==> 2NaCl + Br2
why does reactivity increase going down group 1
as the atoms get bigger and electrons get further away from nucleus the electrostatic attraction gets weaker so they lose the one electron easier
why does reactivity decrease going down group 7
as outer shell gets further away from nucleus the electrostatic attraction gets weaker meaning its harder to gain an electron meaning it will be less reactive as it becomes stable.
