Write down the electronic configuration of the following elements from the given atomic numbers. Answer the following questions with explanation:

a. 3Li, 14Si, 2He, 11Na, 15P Which of these elements belong to the period 3?
→ Let's wrtie the electronic configurations: 3Li: 2, 1 14Si: 2, 8, 4 2He: 2 11Na: 2, 8, 1 15P: 2, 8, 5 Among these elements 14Si (2, 8, 4), 11Na (2, 8, 1) and 15P (2, 8, 5) have three electron shells. Hence, these elements belong to the period 3. 3 Marks
b. 1H, 7N, 20Ca, 16S, 4Be, 18Ar Which of these elements belong to the second group?
→ Let's write the electronic configurations: 1H: 1 7N: 2, 5 20Ca: 2, 8, 8, 2 16S: 2, 8, 6 4Be: 2, 2 18Ar: 2, 8, 8 Among these elements, 20Ca (2, 8, 8, 2) and 4Be (2, 2) have 2 electrons in their outermost shell. Therefore, 20Ca and 4Be belong to the second group. 3 Marks
c. 7N, 6C, 8O, 5B, 13Al Which is the most electronegative element among these?
→ Let's write the electronic configurations: 7N: 2, 5 6C: 2, 4 8O: 2, 6 5B: 2, 3 13Al: 2, 8, 3 Electronegativity increases as we move from left to right in a period. Also, electronegativity decreases as we move down the group. Considering these two aspects, 8O (2, 6) is the most electronegative element among the given elements. 3 Marks
d. 4Be, 6C, 8O, 5B, 13Al Which is the most electropositive element among these?
→ Let's write the electronic configurations: 4Be: 2, 2 6C: 2, 4 8O: 2, 6 5B: 2, 3 13Al: 2, 8, 3 Electropositivity decreases as we move from left to right in a period. Also, electropositivity increases as we move from top to bottom in a group. Considering these two aspects, 13Al (2, 8, 3) is the most electropositive element among the given elements. 3 Marks
e. 11Na, 15P, 17Cl, 14Si, 12Mg Which atom is the largest?
→ Let's write the electronic configurations: 11Na: 2, 8, 1 15P: 2, 8, 5 17Cl: 2, 8, 7 14Si: 2, 8, 4 12Mg: 2, 8, 2 All these elements belong to the third period. Atomic radius goes on decreasing as we move from left to right in a period. Thus, 11Na (2, 8, 1) is the largest atom among the given elements. 3 Marks
f. 19K, 3Li, 11Na, 4Be Which of these atoms has the smallest atomic radius?
→ Let's write the electronic configurations: 19K: 2, 8, 8, 1 3Li: 2, 1 11Na: 2, 8, 1 4Be: 2, 2 Atomic radius goes on decreasing as we move from left to right in a period. Also, atomic radius goes on increasing as we move from top to bottom in a group. Thus, the atomic radius of 4Be (2, 2) is the smallest among the given elements. 3 Marks
g. 13Al, 14Si, 11Na, 12Mg, 16S Which of the above elements has the highest metallic character?
→ Let's write the electronic configurations: 13Al: 2, 8, 3 14Si: 2, 8, 4 11Na: 2, 8, 1 12Mg: 2, 8, 2 16S: 2, 8, 6 Metallic character means the tendency to lose electrons. All these elements belong to the third period. Metallic character goes on decreasing as we move from left to right in a period. Thus, 11Na (2, 8 1) has the highest metallic character among the given elements. 3 Marks
h. 6C, 3Li, 9F, 7N, 8O Which of the above elements has the highest nonmetallic character?
→ Let's write the electronic configurations: 6C: 2, 4 3Li: 2, 1 9F: 2, 7 7N: 2, 5 8O: 2, 6 Nonmetallic character means the tendency to gain electrons. All these elements belong to period 2. Nonmetallic character goes on increasing as we move from left to right in a period. Thus, 9F (2, 7) has the highest nonmetallic character among the given elements. 3 Marks