True or False: One example of a chemical reaction is when H20 (water) melts and changes state from ice to liquid.

False

Explanation:

Water melting from ice into a liquid is not a chemical reaction or chemical change. It is merely a phase change from solid to liquid.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons