A part of the periodic table is given below. The symbols of elements given in the columns are not real.

a) Which are the elements having only one electron in the 4s subshell?

b) Which is the element in s block with the smallest atomic radius?

c) Which are the elements likely to form coloured compounds?

d) Which is the metal with the highest reactivity?

e) Which is the element with the least reactivity?

f) Which is the element in which the last electron is filled in the 4p sub shell? Find its atomic number.

g) Frame as many questions as possible to get each element in this table as the answer.

a) A and C.

Since the element has one electron in a 4s subshell so from this we can find that this element of 4 periods and 1 group.

In d-block elements, the group number will be equal to the sum of total electrons of s subshell and the electrons in preceding d subshell. So A and C are the elements which have one electron in 4s subshell.

b) E

When we go from up to down in a group then a number of shells increases so the radius is also increased. Therefore, the element with the smallest radius in s block is E.

c) D and C

d-block elements (transition elements) form coloured compounds due to the presence of transition element ions. So, element D and C will form coloured compounds.

d) A

Since A is in the bottom in group 1 and the size of A is greater than the other metals due to increment in shells. So, A will loss his 1 electron more easily than other metals and will make compound easily.

e) F

Noble gases are less reactive due to full filled octet. So, F is less reactive.

f) H, Atomic number = 35

If we compare this periodic table ‘s part to the modern periodic table then H is Br which has atomic number 35 and so electronic configuration will be 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵. We can also calculate atomic number by count the elements 2+8+8+17=35.

g)

(i) The lightest metal in s-block?

(ii) The second lightest metal in s-block?

(iii) Which metal is important for strong bones?

(iv) Which transition element ‘s chloride is blue in the dry state?

(v) Which is the most reactive element in the periodic table?

(vi) Which noble gas is used in welding along with Helium?

(vii) Which element in halogen family is used for unsaturation test?

(viii) Which element is used with zinc to make brass alloy?