Answer:
Option B is correct.
4
Explanation:
We know that an atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example, if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.
In given problem we are given with 2 neutrons of helium. We know that the atomic number of He is 2. Thus Mass number of He is,
Number of neutrons + number of proton
2 + 2 = 4
Thus, option B is correct.
Answer:
See explanation
Explanation:
The essence of chemical bonding is in order to attain minimum energy. The minimum energy state is the most stable state of a chemical system.
As the distance of separation between atoms decreases, the potential energy of the system decreases accordingly.
An optimum distance is reached when the two atoms attain the lowest potential energy. This is designated as the bond distance of the two atoms.
Hence two atoms have lower potential energy when bonded than when separated at large distance.
<span>a regultate is to control or direct by a rule, principle, or method.</span>
Answer:
Methods for determining or delivering precise volumes include volumetric pipets and pycnometers; less precise methods include burets, graduated cylinders, and graduated pipets. In this experiment, you will measure masses and volumes to determine density. Four different metal cylinders are investigated.
Explanation:
