How many neutrons are present in 21Ne?

The number of neutrons present : 11

Given

²¹Ne

Required

Number of neutrons

Solution

In the following element notation,

X = symbol of element

A = mass number

   = number of protons + number of neutrons

Z = atomic number

   = number of protons = number of electrons, on neutral elements

So the symbol above shows the mass number Ne: 21

Ne itself has an atomic number of 10, so the number of neutrons :

number of neutrons  = mass number - atomic number

number of neutrons  = 21 - 10

number of neutrons  = 11

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.

frequency, z, and the collision density, z, in carbon dioxide (co2), r 180 pm at 30 °c and 120 kpa