Answer: option <span>A) increases from bottom to top within the group.
Explanation:
</span>It is a known trend that the metallic character of the elements increase from let to right and from top to bottom.
The greater the metallic character the greater the reactivity of the metal.
So, the elements of the columns 1 and 2 are the most reactive metals and among them the elements at the bottom are yet more reactive.
<span>The higher reactivity of the metals that are lower in the periodic table is attributed to the greater total number of electrons.
The greater the total number of electrons the more reactive the metals
as their outermost electrons (the valence electrons which are those that react) are located further from the nucleus and therefore they are held less
strongly, which makes them react more easily.</span>
The half-life of this radioisotope : 12 hr
<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
t=48 hr

The half-life :

Given the equilibrium reaction: 2 A (aq) + 3 B (aq) <— —> 2 C (aq) + D (aq) and equilibrium concentrations of [A] = 0.60M, [B] = 0.30 M, [C] = 0.10 M and [D] = 0.50 M. The Kc value will be:
a. 1.9 c. 2.4 b. 0.15 d. 0.51
Answer . A
B and/or C because velocity is also know as a vector quantity and speed is a scalar quantity
Answer:
The correct options are: Z1) They tend to form cations, and Z4) They tend to form ionic compounds when they combine with the elements of Group VIIA.
Explanation:
The chemical elements that have a tendency of <u>losing their valence electrons</u> and are generally present on the <u>left-side of the periodic table</u> are known as metals.
The general characteristics of metals are malleability, ductility, lustre, high thermal and electrical conductivity.
The metals<u> readily lose their valence electrons</u> present in their valence electron shell to<u> form positively charged ions called </u><u>cation</u>s and thus have <u>low ionization energy</u>.
They also tend to form<u> </u><u>ionic compounds or salts</u><u> </u>with the <u>reactive non-metals belonging to the Group VIIA of the periodic table.</u>
<u>Therefore, </u><u>Z1 and Z4 </u><u>are the properties of most metals.</u>