Now look closely at the patterns in the table. Compare the elements in each column and row. What can we say about elements in the same group and elements in the same period of the periodic table?
Select all the correct answers.

1)The number of electrons in the second energy level increases by one down each column.

2)Elements in the same row have the same number of occupied energy levels.

3)For each column, the last occupied energy level has the same number of electrons.

4)The number of electrons in the first energy level increases by one from Li to Ne.

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.

answer : (a) volume of the gas = 8.67 ×   l

                (b) second virial coefficient b = -1.21226 l/mole

solution :   given,     t = 300k

                                p = 20atm

                                z = 0.86

                                n = 8.2 mmoles = 8.2 × moles

                                r =   0.082 l atm/k/mol

        find,     (a) volume of gas   and (b) second virial coefficient b at 300k.

formula used :            

                          and            

(a)            

                    = \times 0.082\times 300}{20}[/tex]

                    = 8.67 ×   l

(b)      

                    = (0.00867-1) × 8.659

                    = - 8.5839 l/mole