The atomic number of an atom says how many protons it has. This number cant change, since the atomic number is what gives elements their identities (in the periodic table, at least).
The mass number, on the other hand, says how many protons AND neutrons the atom has (so, the sum of P+ and N0). So, electrons have nothing to do with this number.
Atoms are neutrally charged, which means there has to be an equal number of positive and negative particles. The negative particles of an atom are its electrons, and since our atom has 4 protons, it must also have 4 electrons.
Answer:
Volume increases
Explanation:
The balloon when filled at sea level being comparatively close to the center of the earth will have higher pressure due to the influence of gravity and when this balloon is taken to the top of the mountain being away from the center of earth, it will experience a lesser pressure due to low gravity where the amount of force exerted by the air on the object is lesser as compared to to that at the sea level.
Therefore, there will be an increase in volume of the balloon as there is expansion of air on the inside of the balloon as a result of low pressure.
There is not much effect of temperature at both the sea level and the mountain top as the temperature does not impart any energy to the air molecules so as to decrease the volume.
Therefore,there is an increase in the volume of the balloon at the top of the mountain.
Percentage change in volume is given by:

1. Is 49.5
2. Is 8.6
4. Is 6.6
Wait I’m not sure
Answer:
D. Pauli's exclusion principle
Explanation:
<em>A. Newton's laws</em> are related to the motion, they state that "Every object in a state of uniform motion will remain in that state of motion unless an external force acts on it", " Force equals mass times acceleration." and " For every action there is an equal and opposite reaction"
<em>B. Bohr's law </em>depicts an atom as a small, positively charged nucleus surrounded by electrons. These electrons travel in circular orbits around the nucleus.
<em>C. Aufbau principle</em>, also called the building-up principle or the aufbau rule, states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels
<em>D. Pauli's exclusion principle</em> states that <em>no two fermions (e.g., electrons) in an atom can have the same set of quantum numbers,</em> hence they have to "pile up" or "build up" into higher energy levels.
I hope you find this information useful and interesting! Good luck!
4 N/cm^2 is the answer. the way you get this is the formula for pressure is P=F/A. So you would plug in the numbers which would make the equation P=12/3 which you know equals 4. The units for pressure is N/cm^2 or N/m^2
I hope this helps