<u>Answer:</u>
The idea that as we go down the periodic table the atomic radius increases and first ionization energy decreases was given by Henry Moosely after he made some changes in the periodic table, the theory proposed by Mendeleev.
<u>Explanation:</u>
- Both these trends were well explained and supported by genuine reasons.
- As we go down a group in periodic table, a new shell is added at each level, which increases the size and hence the radius of the atom and the size of atom increases which means the outermost shell is increasingly moving farther from the atom.
- Due to this fact, electrons experience less attractive force from the nucleus and electrons are easily removed, so the first ionization energy decreases.
The correct classification of the reactions are as follows:
<span>1) 2Mg(s) + O2(g)----> 2MgO (s)
It is a synthesis reaction or a combination reaction. It involves the bonding of the reactant molecules forming one single molecule with new set of properties.
2) Na(s) + Cl2(g)------> NaCl(s)
It is a combination reaction as well, the same as the first reaction.
3). PbCO3(s)------> PbO(s)+Co2(g)
It is a decomposition reaction where a single molecule is breaks down into multiple molecules.
4). Ch4(g) + 2O2(g)----> CO2(g) + 2H2O(g)
It is a combustion reaction since it involves the reaction with oxygen and the production od carbon dioxide and water.</span>
Answer:
2H3PO4 + 3Ca(OH)2 = Ca3(PO4)2 + 6H2O
3CaO + P2O5 = Ca3(PO4)2
Answer: gas and alkaline earth metal
Explanation:
