Answer:
Groups show similar chemical properties about the elements
Explanation:
The periodic table is divided into groups and periods. Groups are vertical while periods are horizontal.
All elements in the same group possess the same number of outermost shell electrons. This number of outermost shell electrons controls the reactivity of the elements in the group.
Hence, groups show similar chemical properties of the elements in them, Groups separate elements into families which assist in the speedy study of elements.
Somewhat false
observations can be made of a model of the statue of liberty, say, or in real line
The amount of chemical energy is equal to the amount of heat and light energy.
This is due to the principle of conservation of energy, which states that the total energy of a system remains constant.
Sodium-22 remain : 1.13 g
<h3>Further explanation
</h3>
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually, radioactive elements have an unstable atomic nucleus.
General formulas used in decay:

T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
half-life = t 1/2=2.6 years
T=15.6 years
No=72.5 g
