The periodic table is useful tool for chemist since we can see what is the atomic and mass number for each atom.
Atomic number is equal to how many protons and electrons in it
Mass number is equal to protons + Neutrons.
The atomic mass is the average mass of all the isotopes. The atomic number is the number of protons in the nucleus of an atom. In an uncharged atom the atomic number is also equal to the number of electrons.
Hope this helps!
<u>Answer:</u>
<em>1) ∆H is positive
Endothermic
</em>
<em>2)
Endothermic </em>
<em>3) Energy is absorbed
Endothermic
</em>
<em>4)
Exothermic
</em>
<em>5) ∆H is negtive
Exothermic
</em>
<em></em>
<u>Explanation:</u>
∆H is called as enthalpy change
It is also called as Heat of reaction
Energy is required for the bond to break a bond.
Energy is released when a bond is formed.

that is

We see in this equation, bonds between hydrogen and chlorine molecules gets broken and on the right side bond is formed in HCl.
If energy of products greater than energy of reactants then the reaction enthalpy change is endothermic .
If energy of products lesser than energy of reactants then the reaction enthalpy change is exothermic .
For example



(positive hence endothermic)



(negative hence exothermic)
Answer:
V Ta is more reactive, hope this helps!
uhmm, white.
Explanation:
you'll basically look like blind ig