1. This element has 12 electrons when the atom is electrically neutral.
2. This element is an alkaline-earth metals group. It has 20 protons.
3. This element has 7 electrons when the atom is electrically neutral.
4. An isotope of this element has 8 neutrons and a mass of 14.
5. This element has a chemical symbol Hg.
6. This element belongs to the same group as aluminum (Al) and has an atomic mass of 69.72.

1. Magnesium(Mg)

2.Calcium(Ca)

3.Nitrogen(N)

4.Carbon(C)

5.Mercury(Hg)

6.Gallium(Ga)

Explanation:

1.Neutral means same no. of protons and electrons which is atomic number.So element with Atomic number 12 is Magnesium.

2. No. of protons = Atomic number.So element with Atomic number 20 is Calcium.

3.Neutral means same no. of protons and electrons which is atomic number.So element with Atomic number 7 is Nitrogen.

4.C-14 isotope has two extra neutrons making it 6+2= 8 neutrons.

5.Mercury(Hg) is the name of element.

6.Gallium(Ga) and Aluminium together belongs to Aluminium family.

you didnt put any of the following

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