why the 18th group is called as zerovalent group
18th group elements are called zerovalent group because they neither accept electrons nor do they give electrons. Thus, they exhibit zero valency.
The atomic number of hydrogen is 1 and that of helium is 2. Why is hydrogen(a non-metal) placed in the first group and helium in the 18th group?
Why are third group elements called bridge elements?
Why is blood group. O called the universal donor?