Find the number of valence electrons in the following atoms using the periodic table:

The number of valence electrons corresponds to the number of electrons in the outermost shell of an atom. To find this, we look at the group number in the periodic table:

  • (a) Boron (B): Boron is in Group 13 of the periodic table. Elements in Group 13 have 3 valence electrons. Therefore, boron has 3 valence electrons.

  • (b) Neon (Ne): Neon is in Group 18, which is the noble gas group. Elements in Group 18 have 8 valence electrons. Therefore, neon has 8 valence electrons.

  • (c) Rubidium (Rb): Rubidium is in Group 1 of the periodic table. Elements in Group 1 have 1 valence electron. Therefore, rubidium has 1 valence electron.

  • (d) Barium (Ba): Barium is in Group 2 of the periodic table. Elements in Group 2 have 2 valence electrons. Therefore, barium has 2 valence electrons.

  • (e) Arsenic (As): Arsenic is in Group 15 of the periodic table. Elements in Group 15 have 5 valence electrons. Therefore, arsenic has 5 valence electrons.

These valence electrons are important because they determine an element’s chemical reactivity and bonding behavior.

Related Questions:

  1. Explain how elements attain stability.
  2. Describe the ways in which bonds may be formed.
  3. Describe the formation of a covalent bond between two non-metallic elements.
  4. Explain with examples single, double, and triple covalent bonds.
  5. Represent the formation of cations for the following metal atoms using electron dot structures:
  6. A sample of sulfur from a volcano was analyzed to give the following composition of isotopes (Atomic No. of S = 16):
  7. An atom of an element has an atomic number of 9 and a mass number of 19:
  8. Define ionic bond and give an example.
  9. State octet and duplet rules.
  10. Explain the formation of a covalent bond between two nitrogen atoms.
  11. How does Al form a cation?
  12. Draw an electron cross and dot structure for an H₂O molecule.
  13. Describe the importance of noble gas electronic configuration.
  14. The atomic number of an element is 23, and its mass number is 56.
  15. The atomic symbol of aluminum is written as Al. What information do you get from it?
  16. Write the valence shell electronic configuration of an element present in the 3rd period and Group IIA.
  17. Define halogens.
  18. Which atom has a higher shielding effect, Li or Na?
  19. Explain why Na has higher ionization energy than K.
  20. Arrange the elements in each of the following groups in order of increasing ionization energy: