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.
All copper atoms have atomic number 29: all their nuclei contain 29 protons. But they also contain uncharged particles called neutrons. ... The two different kinds of atom are called isotopes of copper. The neutron has a mass very similar to that of the proton, so the two isotopes differ in mass.
This is not chemistry but it's A, off top.
<h2>
Answer:</h2>
<h3>Hg2 ( NO2 )2</h3>
<h2>Explanation:</h2>
<h3>Formula of mercury ( 1 ) dioxonitrate 111 is Hg2 ( NO2 )2//</h3>
