Atoms are made of 3 types of subatomic particles ; protons, neutrons and electrons
protons and neutrons are located inside the nucleus and electrons are found in energy shells around the nucleus. Protons are positively charged, electrons are negatively charged and neutrons are neutral. elements in their ground state are neutral with equal amounts of protons and electrons.
Atomic number is the number of protons. atomic number is characteristic for the element.
atomic number of Be is 4 therefore Be has 4 protons
answer is B. 4
The chemical change can occur can be find if you mix the two solids in one direction
Solution :
Given :
Amount of anserine solution = 0.200 M
pH value is = 7.20
Preparation of 0.04 M solution of anserine from the 0.2 M solution.
0.2 M x 
= 0.04 M x 1000 ml
= 200 ml
So the 200 ml of 0.2 M anserine solution is required to prepare0.04 M of anserine.
0.1 M x = 0.04 x 1000 ml
= 400 ml
Therefore, 400 ml of HCl is needed.
