The second period of the modern periodic table comprises
2 elements
8 elements
18 elements
36 elements
Which of the following sets are members of same family?
Na ,Mg, Ca
L i ,Na,K
O,F,Cl
O,N,P
The atomic size of element when we move from left to right
decrease
increase
same
zero
Elements have the same number of valence electrons are placed in same
group
table
period
not possible
Hydrogen resembles with any one of the following
Na, C
alkali metal, halogen
alkali metals, alkaline earth metals
halogen, alkali metals
The long form of periodic table is based on Bohr’s atomic model. It consists of eighteen groups and seven periods. The periods are numbered 1, 2, 3, 4, 5, 6, and 7 and each number respectively refers to the addition of last electron to the 1st, 2nd, 3rd, 4th…etc., energy levels.Which atomic number represents an element of period 4 of the periodic table?
10
14
17
20
An isotope of which is used in the treatment of goiter?
Iodine
Cobalt
Chlorine
Uranium
