Answer: 
Explanation:
Electron gain enthalpy is defined as energy released on addition of electron to an isolated gaseous atom.
The amount of energy released will be maximum when the tendency to attract electrons is maximum. As flourine has atomic number of 9 and has electronic configuration of 2,7. It can readily gain 1 electron to attain stable noble gas configuration and hence liberates maximum energy.
Hi! Well the formula of kinetic energy is Ke = 0.5 x M x V^2
0.5 x 0.5 x 10^2
0.25 x 20
5 J (joule)
Lithium, sodium, potassium, rubidium, cesium, and francium
Look it up online you will find it
It is (CI) bromine
because, <span>Halogen element, any of the six nonmetallic elements that constitute Group 17 (Group VIIa) of the periodic table. The halogen elements are </span>fluorine (F)<span>, </span>chlorine (Cl), bromine (Br<span>), iodine (I), astatine (At), and tennessine (Ts).</span>
