Everything Science Grade 10

4.6 CHAPTER 4. THE ATOM

c.x 4 Be

12. Which of the following are isotopes of^2412 Mg:

a.^1225 Mg

b.^2612 Mg

c.^2413 Al

13. If a sample contains 69% of copper-63 and 31% of copper-65, calculate

the relative atomic mass of an atom in that sample.

14. Complete the following table:

Element or ion Electron configuration Core electrons Valence electrons

Boron (B)

Calcium (Ca)

Silicon (Si)

Lithium ion (Li+)

Neon (Ne)

More practice video solutions or help at http://www.everythingscience.co.za

(1.) 0019 (2.) 001a (3.) 001b (4.) 001c (5.) 001d (6.) 001e

(7.) 001f (8.) 001g (9.) 001h (10.) 001i (11.) 001j (12.) 001k

(13.) 001m (14.) 001n

94 Chemistry: Matter and Materials