16. (i) The non-metallic character of the elements:-   A. decreases.   B. increases.   C. remains the same.   D. depends on the period.   17. (ii) The electronegativity:-   A. depends on the number of valence electrons.   B. remains the same.   C. decreases.   D. increases.   18. (iii) The ionization potential:-   A. goes up and down.   B. decreases.   C. increases.   D. remains the same.   19. (iv) The atomic size:-   C. remains the same.   D. sometimes increases and sometimes decreases.   A. decreases.   B. increases.   20. (v) The electron affinity of the elements in groups 1 to 7:-   A. goes up and then down.   B. decreases and then increases.   C. increases.   D. decreases.