4. An element M combines with oxygen to form M2O which is a solid with high melting point
a) What is the valency of M?
b) Which group does M belong to?What is the name given to that
group of elements?
c) Name two other elements of the same group.
d) Give two chemical properties of the elements of this group.
e) What kind of bonding would you find in M2O?
1) The valency of M is 1.
2) M belongs to group 1 . These are known as alkali metals.
3) The other two elements of this group are lithium and sodium.
4) Chemical properties are :
2) M belongs to group 1 . These are known as alkali metals.
3) The other two elements of this group are lithium and sodium.
4) Chemical properties are :
Alkali metals are highly reactive due to their low ionization enthalpy. As we move down the group, the reactivity increases.
c) They react with water to form respective oxides or hydroxides. As we move down the group, the reaction becomes more and more spontaneous.
b) They react with water to form their respective hydroxides and dihydrogens. The general reaction for the same is given as
c) They react with dihydrogen to form metal hydrides. These hydrides are ionic solids and have high melting points.
