Groups in the periodic table Flashcards
What are group 1 metals known as
Alkali metals
What are the group 1 metals
Lithium, Sodium Potassium, Rubidium, Caesium, Francium
Physical properties of group 1 metals
Low meltimg and boiling points
Very soft (they can be cut with knife)
What do alkali metals form
ionic compound because they lose their electron as its really easy and they only have one electron on the outer shell
Why are group 1 metals very reactive?
They readily lose their single outer electron to form a 1+ ion with a stable electronic structure
The more readily a metal loses it’s outer electron, the more reactive it is - so the group 1 metals are very reactive
Why do the metals get more reactive as you go down the group ?
(group 1)
As you go down group 1, the alkali metals get more reactive. The outer electron is more easily lost because its futhre away from the nucleus (the atomic radius is larger) - so it’s less strongly attracted to the nuclues and less energy is needed to remove it
What are group 7 metals called
Halogens
Describe Fluorine
Gas - at room temperature
Yellow
Low melting and boiling points
Most reactive
Describe Chlorine
More reactive
Gas at room temperature
Green
Low melting and boiling point
Describe Bromine
Liquid at room temperature
Brown-red
What is the test for chlorine?
Hold a piece of damp blue litmus over it.
Chlorine will bleach the litmus paper, turning it white
It may also turn red for a moment first as the solution of chlorine is acidic
Describe iodine
Dark grey crystalline solid whicg gives off a purple vapour when heated
Describe astatine
Solid at room tempertature
Grey-black solid
What does diatomic molecules mean?
The halogens exist as diatomic molecules (e.g. Cl₂, Br₂)
Sharing one pair of electrons in a covalent bond giving both atoms a full outer shell
Does the melting point increase or decrease as you go down the group?
(group 7)
The melting point increases down the group therefor they become more solid as you go down
What does a halogen atom form?
It only needs to gain one electron to form a 1- ion with a stable electronic structure
What is the trend in reactivity in group 7 ?
As you go down group 7, the halgons become less reactive as it gets harder to attract the extra electron to fill the outer shell when it’s further away from the nuclues.
(atomic radius is larger)
What do halogens form with metals
The halogens will react vigorously with some metals to form salts called ‘metal halides’
What are hydrogen halides
Halogens can also react with hydrogen to form hydrogen halides
Hydrogen halides are soluble, and they can dissolve in water to form acidic solutions
What is relative molecular mass?
It gives us an idea of the size of a molecule
(As you go down group 7 the relative molecular mass increases (they get bigger))
What do halogens form with metals and non-metals?
When halogens react with non-metals they form covalent bonds
When halogens react with metals they form ionic bonds
What are group 0 gases called?
Nobels gases
Describe nobel gases
They are colourless
They are monatomic (made up of single atoms)
They are inert
They have a full outer shell of electrons, they don’t easily gain or lose electrons
Are noble gases flamable
They’re non-flamable as they are inert
What does inert mean?
Extremely unreactive
Describe the trend in Group 0
The boiling point, melting point and density all increase as you go down group 0
Use of Argon
Filament lamps (light bulbs) since it’s non-flamable it stops very hot filament from burning away
Uses of Helium
Used in airships and party balloons as it has a low density than air so it makes balloons float.
It is also non-flamable which makes it safer to use than hydrogen gas
Uses of krypton and Xenon
Flash photography
thye are used to stop the flash filament from burning up during the high temperature flashes
Use of neon
high-voltage indicators or glow signs
