Groups 1 and 7 Flashcards
What are group 1 elements called?
They are called alkali metals
What are group 7 elements called?
They are called halogens.
What are two physical properties of the alkali metals?
. Are soft (they can be cut with a knife)
. Have relatively low melting points
. They have low densities (the first 3 in group 1 can float on water)
Going down group 1, does the melting point increase or decrease?
Decreases
What is pH?
Scale of acidity or alkalinity. A pH (power of hydrogen) value below 7 is acidic (1 being most acidic),7 being neutral, and a pH value above 7 is alkaline (higher meaning more alkaline (14))
The alkali metals react with water to produce….
…a metal hydroxide and hydrogen.
Does the reactivity increase or decrease going down group 1?
It increases as it is easier to lose 1 electron than gain 7.
Why is sodium more reactive than lithium?
Sodium loses an outer electron more easily than lithium because its outer electron is further from the nucleus.
What happens to the universal indicator when it is added to the solution produced when an alkali reacts with water?
It would turn purple.
Does the melting and boiling point increase or decrease going down group 7?
The melting points and boiling points of the halogens increase going down group 7.
Why does the melting and boiling point increase for the halogens?
It increases because :
. the molecules become larger
. the intermolecular forces become stronger
. more energy is needed to overcome these forces
Where are alkali metals stored?
They are stored in oil to keep water and air away from them.
Why does the reactivity increase as you go down the group 1?
. the atoms get larger
. the outer electron gets further from the nucleus
. the attraction between the nucleus and outer electron gets weaker – so the electron is more easily lost
Does reactivity increase or decrease as you go down group 7?
It decreases
Why does reactivity decrease as you go down group 7?
As you go down group 7, the reactivity of the halogens decreases because the atomic mass of the halogens increases. They increase in electron shells; so the atoms are larger as you go down the group. Therefore, the attraction of the outer electron to the nucleus decreases as you go down group 7.
Why do the melting and boiling points of group 1 metals decrease as you go down?
It decreases because there is a decrease in the forces of attraction between the atoms.
What is shielding?
When you have more shells and the forces get weaker between the nucleus and the outer most electron.
What is reduction?
The loss of oxygen, gain of electrons, or gain of hydrogen by a substance during a chemical reaction.
What is oxidation?
The gain of oxygen, or loss of electrons, by a substance during a chemical reaction.
What is a redox reaction?
When reduction and oxidation take place at the same time.
What are two extraction methods for metals?
Electrolysis and Reduction with Carbon
What is Electrolysis?
The decomposition (breakdown) of a compound using an electric current. In principle, any metal could be extracted from its compounds using electrolysis. However, large amounts of
electrical energy is needed to do this, so electrolysis is expensive.
What is reduction with carbon?
If a metal is less reactive than carbon, it can be extracted from its compounds by heating it with carbon as carbon would displace it. It can only be used for elements less reactive than it.
What are 2 advantages of recycling used metals rather than mining and extracting the raw material:
- It is much better for the environment as mining would release greenhouse gases which contribute to global warming.
- It conserves the natural resources of the metal.
