Select from each group the species which has the smallest radius, stating the appropriate reason.

• $\mathrm{Si}, \mathrm{P}, \mathrm{Cl}$

Choose from the following :

${}_4\mathrm{Be}$, ${}_9\mathrm{F}$, ${}_{19}\mathrm{K}$, ${}_{20}\mathrm{Ca}$

The element having one electron in its outermost shell.

Choose from the following :

${}_4\mathrm{Be}$, ${}_9\mathrm{F}$, ${}_{19}\mathrm{K}$, ${}_{20}\mathrm{Ca}$

Two elements of the same group.

Chlorine is an element in period $3$ of the Periodic Table. Bromine is found in period $4$ of the Periodic Table. These two elements may be from different periods of the periodic table, but they have many similar properties.

Complete the given table.

Chlorine is an element in period $3$ of the Periodic Table. Bromine is found in period $4$ of the Periodic Table. These two elements may be from different periods of the periodic table, but they have many similar properties. Explain why the properties of chlorine and bromine closely resemble one another.

Chlorine is an element in period $3$ of the Periodic Table. Bromine is found in period $4$ of the Periodic Table. These two elements may be from different periods of the periodic table, but they have many similar properties. Lithium is an element from Group I of the Periodic Table. Write the formula of the compound formed between lithium and chlorine.