Question

The element/s present in the ${4^{th}}$ period is:
A.Chlorine
B.Iodine
C.Fluorine
D.Bromine

Answer 1

A sequential arrangement of elements in a chart, on the basis of atomic number is coined as periodic table. Horizontal rows are called periods and vertical columns are called groups. To approach the question, we should know which elements are present in the fourth period.

Complete answer:
There are a total of seven periods and eighteen groups. In the ${4^{th}}$period, there are eighteen elements.
They are named as follow:

Name of the element	Symbol	Atomic number, Nature
Potassium	$K$	19, alkali metal
Calcium	$Ca$	20, alkaline earth metal
Scandium	$Sc$	21, transition metal
Titanium	$Ti$	22, transition metal
Vanadium	$V$	23, transition metal
Chromium	$Cr$	24, transition metal
Manganese	$Mn$	25, transition metal
Iron	$Fe$	26, transition metal
Cobalt	$Co$	27, transition metal
Nickel	$Ni$	28, transition metal
Copper	$Cu$	29, transition metal
Zinc	$Zn$	30, metal
Gallium	$Ga$	31, metal
Germanium	$Ge$	32, metalloid
Arsenic	$As$	33, metalloid
Selenium	$Se$	34, metalloid
Bromine	$Br$	35, non metal
Krypton	$Kr$	36, radioactive isotopes exist.

From the above table, we get to know that out of the given options, $Br$ belongs to period 4.
Thus, option D. Bromine is the correct answer to the given option.
Note:
Period 4 is the first period of the transition series. This period contains elements like Potassium and Calcium which are important from a biological point of view. Bromine, an element belonging to group 17 and period4, is the only non-metal that is liquid at room temperature.Krypton has radioactive isotopes and is used in lighting and photography.