11. The constituents of an atoms are
a. protons
b. neutrons
c. electrons
d. positron

12. The number of protons in an atom is called its
a. isotope number
b. atomic number
c. atomic weight
d. none of the above

13. The maximum number of electrons in third orbit can be
a. 3
b. 6
c. 12
d. 18

14. Valence electron are the
a. loosely packed electrons
b. mobile electrons
c. electrons represent in the outermost orbit
d. electrons that do not carry any charge

15. Which of the following element has lowest atomic number
a. B
b. Al
c. Ga
d. In

16. Which of the following element does not occur in third group of periodic table
a. Indium
b. Helium
c. Aluminium
d. Boron

17. The atomic number of silicon is 14. It can be therefore concluded that
a. a silicon atom contains 14 electrons
b. a silicon atoms contain 14 neutrons
c. a silicon atoms contains 14 electrons
d. all of the above

18. If the atomic number of germanium is 32 , the number of electrons in the outermost shell will be
a. 2
b. 3
c. 4
d. 6

19. Which of the following elements does not have three valence electrons
a. Boron
b. Aluminium
c. Germanium
d. Phosphorous

20. Which of the following elements does not have five valence electrons
a. Phosphorous
b. Arsenic
c. Antimony
d. Indium