Lecture 1 Flashcards
Why do elements in the same group have similar reaction?
All the elements in a group have similar reactions, because they have the same
number of valency electrons
What are Group 1 called?
The alkali metals
What are Group 2 called?
The alkaline earth metals
What are Group 7 called?
The halogens
What are Group 0 called?
The noble gases
4 examples of alkali metals
Lithium, sodium, potassium and cesium
Physical properties of alkali metals
They are softer than most metals (can be cut with a knife).
They are good conductors of heat and electricity.
They have low density.
They have low melting and boiling points.
How does sodium and lithium react with water?
They react violently with water, giving hydrogen and a hydroxide.
What happens in the experiment with potassium and water?
It reacts vigorously with water. Burns violently with a purple flame and disappears extremely quickly.
Chemical reaction between alkali metals and chlorine
They burst into flame and burn brightly forming chlorides.
Chemical Reaction between alkali metals and oxygen
They burn fiercely to form oxides
What are alkali metals stored under
Stored under oil to prevent reaction with oxygen and water.
Why are alkali metals so reactive?
Because they need to lose only one electron, to gain a stable outer shell. So they have a strong drive to react with other elements and compounds.
Why does reactivity increase down group 1
This is because the outer electron is getting further away from the nucleus. This means the attraction is lower. This outer electron is easier to lose.
What’s the reason for lithium holding onto its outer electron more strongly than sodium?
Because it has a lower atomic radius than sodium so nuclear attractive force acts on valence shell more on lithium.
Name 4 alkaline earth metals
Beryllium, magnesium, calcium and barium
Alkaline metals reaction with oxygen
They burn in air and more rapidly in oxygen. They get more reactive with oxygen going down the group.
Uses of alkaline metals?
Limestone (calcium carbonate)= building material/ cement
Slaked line (calcium hydroxide)= used by the farmers to raise the pH of acidic soil.
Barium= used to track the movement of meals on xrays in the field of gastroenterology.
Give a reason to explain why atomic radii decrease from Li to F.
Charge increases as the atomic number increases. Force of attraction between valency electrons and nucleus increases.
What’s the most metallic and non-metallic elements
Francium is the most metallic as it can lose electrons quickly due to its larger atomic size. In contrast, F is most non-metallic as it can gain electrons rapidly due to its smallest atomic size.
