Answer:
See below.
Explanation:
A lot of heat is produced in this reaction so much that the sodium catches fire. If there is a lot of water and just a small piece of sodium it will not catch fire. Potassium reacts more vigorously than sodium and will always catch fire.
Answer : The correct option is,
Solution :
Formula used :
where,
E = change in energy
h = Planck’s constant =
c = speed of light =
= wavelength = 2.21 m
Now put all the given values in the above formula, we get the energy of an atom.
Therefore, the energy of an atom is,
Answer:
28
Explanation:
it states that the atom is neutral, meaning the number of electrons and protons are the same. so if there are 13 electrons, there are 13 protons. And the mass number is neutrons plus protons. So 13+15 is 28
Its the third one ....Single Replacement