Given the table below, answer the following questions:

\begin{tabular}{|c|c|c|c|c|c|c|c|}
\hline
[tex]$I_A$[/tex] & [tex]$II_A$[/tex] & [tex]$III_A$[/tex] & [tex]$IV_A$[/tex] & [tex]$V_A$[/tex] & [tex]$VI_A$[/tex] & [tex]$VII_A$[/tex] & [tex]$VIII_A$[/tex] \\
\hline
[tex]$Li$[/tex] & [tex]$Be$[/tex] & B & C & & & & [tex]$He$[/tex] \\
\hline
[tex]$Na$[/tex] & [tex]$Mg$[/tex] & [tex]$Al$[/tex] & Si & [tex]$N$[/tex] & [tex]$O$[/tex] & [tex]$F$[/tex] & [tex]$Ne$[/tex] \\
\hline
[tex]$K$[/tex] & [tex]$Ca$[/tex] & & & [tex]$P$[/tex] & [tex]$S$[/tex] & [tex]$Cl$[/tex] & [tex]$Ar$[/tex] \\
\hline
\end{tabular}

1. Which one has a bigger atomic size?
i. [tex]$Na$[/tex] or [tex]$Mg$[/tex]
ii. [tex]$O$[/tex] or [tex]$S$[/tex]

2. What is the valency of [tex]$Be$[/tex] and [tex]$O$[/tex]? Explain.

3. Which one is more reactive, [tex]$F$[/tex] or [tex]$Cl$[/tex]? Explain.

4. How many valence electrons do [tex]$Al$[/tex] and [tex]$Ar$[/tex] have?

5. What is the valency of [tex]$Ne$[/tex]? Explain.



Answer :

Let's carefully work through the questions based on the given periodic table. Here is a step-by-step solution:

### Bigger Atomic Size Comparison:
i. Comparison between Na and Mg:
- The atomic size generally decreases from left to right within a period in the periodic table. Sodium (Na) is in Group I_A and Magnesium (Mg) is in Group II_A in the same period.
- Since Sodium (Na) is to the left of Magnesium (Mg), Sodium (Na) has the bigger atomic size compared to Magnesium (Mg).

ii. Comparison between O and S:
- The atomic size generally increases from top to bottom within a group in the periodic table. Oxygen (O) is in Group VI_A and is situated above Sulfur (S).
- Since Sulfur (S) is below Oxygen (O) in the group, Sulfur (S) has the bigger atomic size compared to Oxygen (O).

### Valency:
b. Valency of Be and O:
- Beryllium (Be) is in Group II_A. Elements in this group typically have a valency of 2 because they tend to lose two electrons to achieve a stable electron configuration.
- Oxygen (O) is in Group VI_A. Elements in this group typically have a valency of 2 as well because they tend to gain or share two electrons to complete their octet and achieve a stable electron configuration.

### Reactivity:
c. Reactivity comparison between F and Cl:
- In the halogen group (Group VII_A), reactivity generally decreases down the group. Fluorine (F) is above Chlorine (Cl) in this group.
- Therefore, Fluorine (F) is more reactive than Chlorine (Cl) because it has a smaller atomic radius and higher electronegativity, making it more eager to gain an electron to achieve a stable configuration.

### Number of Valence Electrons:
d. Valence electrons of Al and Ar:
- Aluminum (Al) is in Group III_A. Elements in this group have 3 valence electrons.
- Argon (Ar) is in Group VIII_A (also known as Group 18 or the Noble Gases). Elements in this group have 8 valence electrons, except for Helium (He), which has 2.

### Valency:
e. Valency of Ne:
- Neon (Ne) is a noble gas in Group VIII_A. Noble gases are very stable and generally do not form compounds because they have a complete outer electron shell.
- Therefore, the valency of Neon (Ne) is 0 because it does not need to gain, lose, or share electrons to achieve stability.

### Final Summary:
1. The atomic size comparison:
- i. [tex]\( \text{Na} \)[/tex] is bigger than [tex]\( \text{Mg} \)[/tex]
- ii. [tex]\( \text{S} \)[/tex] is bigger than [tex]\( \text{O} \)[/tex]

2. The valency:
- [tex]\( \text{Be} \)[/tex] has a valency of 2
- [tex]\( \text{O} \)[/tex] has a valency of 2

3. Reactivity comparison:
- [tex]\( \text{F} \)[/tex] is more reactive than [tex]\( \text{Cl} \)[/tex]

4. Valence electrons:
- [tex]\( \text{Al} \)[/tex] has 3 valence electrons
- [tex]\( \text{Ar} \)[/tex] has 8 valence electrons

5. The valency of [tex]\( \text{Ne} \)[/tex]:
- [tex]\( \text{Ne} \)[/tex] has a valency of 0

I hope this clarifies the answers to your questions!

Other Questions