Question

The atomic number of a halogen element in the fourth period is $35$ if true enter $1$, else enter $0.$

Answer 1

Hint: The elements, which are positioned on the left of the nobles gases on the periodic table are named as the halogens. They belong to $Group-17$. The elements present in this group are non-metallic.

Complete step by step answer: We know that in the periodic table, the Group-17 belongs to the halogens family. The halogen family is seen before the noble gases. The number of valence electrons is seven, and it needs only one extra electron to complete the octet. Due to this reason, halogens are more reactive than other groups consisting of the non-metals. The oxidation state of halogen is $-1$
The elements present in the halogen family is,
- Fluorine
- Chlorine
- Bromine
- Iodine
- Astatine
Fluorine belongs to second period and has atomic number $9.$
Chlorine belongs to third period and has atomic number $17.$
Bromine belongs to fourth period and has atomic number $35.$
Iodine belongs to fifth period and has atomic number $53.$
Astatine belongs to sixth period and has atomic number $85.$

From the above list of halogens along with their atomic number, we can see the atomic number of a halogen element in the fourth period is ${\text{35}}{\text{.}}$
Thus, the given statement is true and therefore, enters ${\text{1}}{\text{.}}$

Note:
- Halogen has the capability to form diatomic molecules in their elemental state.
- Halogens could be hydrogen halides and hydrogen oxoacids.
- Halogen exhibit a oxidation state of $ - 1.$
- Bromine is liquid at room temperature, whereas fluorine and chlorine are gases at room temperature.
- Iodine and astatine are solids at room temperature.
- Fluorine is highly electronegative and astatine is least electronegative.