The answer is A! Heat energy is thermal energy. To remember all Energy use M.E.L.T.S!
M- Mechanical energy
E- Electrical energy
L- Light energy
T- Thermal energy
S- Sound energy
Answer:
A. The increase in the mass of the magnesium oxide was due to oxygen atoms in the air.
Explanation:
Burning occurs in the presence of oxygen. A chemical combination occurs between Mg and O in that the atom of magnesium attracts one another.
Mg + O₂ → MgO
Starting with the magnesium, on reacting with oxygen a new compound forms. This is why there is mass increase in the MgO compared to the starting material.
The atomic radius increases as we go down a group/family on a periodic table.
Explanation:
"Atomic radius" is defined as the "one-half of the distance" between the "nuclei of two atoms". While moving down the group in a periodic table there is an "increase in quantum number n" which allows the valence electrons to occupy on higher levels. This shows that the valence electrons move away from the nucleus, which makes them to be loosely held. Thus, atomic radius is large.
Similarly while moving across the periodic table from "left to right" the atomic radius gradually decreases.
