Ques. No. 1
 

Ques. No. 1   . What do you mean by metallic character of an element ? How does it we go down a group ? Give reason for this variation. 6. Why metallic oxides are basic in nature whereas non-metallic oxid acidic in nature ? 7. How does the atomic size vary as we go down a group and move left to in a period ? Write the reason behind it. SHORT ANSWER TYPE QUESTIONS (3 Marks) l. Four elements P, Q, R and S have atomic number 12, 13, 14 a respectively Answer the following : (a) (b) (c) (b) 66 What is the valency of Q ? Classify these elements as metals and non-metals. Which of these elements will form the most basic oxide ? How do we calculate the valency of an element from its el configuration ? How does the valency vary in a period ? Science Class - 10

Dear student
Four element P,Q,R, S have atomic no 12,13,14 ,15 respectively
1)
Atomic number of Q = 13 electronic configuration = 2, 8, 3 Since 3 electrons are present in valence shell, therefore valency of Q is 3

2) electronic configuration of P = 2,8,2 (atomic number given as 12) electronic configuration of Q = 2,8,3 (atomic number given as 13) electronic configuration ofR = 2,8,4 (atomic number given as 14) electronic configuration of S = 2,8,5 (atomic number given as 15)

Metals are the ones which lose electrons to achieve stable configuration that is having eight electrons in valence shell. Since P and Q can easily donate 2 and 3 electrons respectively, therefore they both are metals. Whereas R can gain or lose four electrons to attain stable configuration hence it is a metalloid. In S, it easy to gain three electrons instead of losing 5 electrons, therefore it is a non metal.

3) The most basic oxide is formed by P with atomic number 12 that is magnesium. Metal oxide is MgO.
Oxide formed by Q that is aluminium is amphoteric. (Al₂O₃). Other elements, R and S forms acidic oxides.

Regards