Answer:
group 18
Explanation:
The noble gases (Group 18) are located in the far right of the periodic table and were previously referred to as the "inert gases" due to the fact that their filled valence shells (octets) make them extremely nonreactive
1 mol of silver means 6.02 x 10²³ Ag atoms
number of moles of silver
= 2.408 × 10²⁴ Ag atoms x <u> 1 mol Ag </u>
6.02 x 10²³ Ag atoms
= 0.4 x 10
<u>= 4 moles</u> Ag
<u>4 moles of silver</u> are equivalent to 2.408 × 10²⁴ atoms
Answer: a. It receives a hydrogen ion.
Explanation: Base is a species which is capable of donating its negative quantity and accepting the positive one.
For example, ammonia is considered as a base because it is capable of donating its lone pairs of electrons and can accept an proton as well.
Here, out of the given options, Hydrogen 
is a proton which is acting as a positive species and hydroxide ion 
is a negative species.
Thus, option (A) is the correct answer as it will receive a hydrogen ion from another base making itself a conjugate acid.
Answer:
option C. Addition of protons to the atomic nucleus.
Explanation:
Elements are fundamentally made up of atoms. Atoms in turn has three sub particles.
These particles are; neutrons, electrons and protons.
The sub particles responsible for the mass of an atoms is basically the protons and neutrons. Going through the options;
The correct option is option C. Addition of protons to the atomic nucleus.
atoms are made of 3 types of sub atomic particles; neutrons, protons and electrons
atomic number is the number of protons which is characteristic for the element. Atoms of the same element have the same number of protons.
mass number is the sum of the neutrons and protons.
Isotopes are atoms of the same element with different mass numbers. since they are the same element number of protons are the same but number of neutrons vary.
therefore 2 isotopes are of the same element so they have the same number of protons.
