it is an endothermic because water can not give off heat it can only take from others like if you were to boil water the water is endothermic and the heat is the exothermic
Answer:
At earlier times elements were arrangrd on the basis of their atomic masses to study their properties easily but there were various problems like isotopes needs different position in perodic table.
After discovery of atomic number modern periodic table was created on the basis of atomic number (number of proton) that is unique for each element and varies regularly. So study of a group of elements is much easier than each element seperately that is why modern periodic table was formed.
Explanation:
<span>
Mn²⁺ + 4H2O -----> MnO4⁻ + 8H⁺ +5e⁻ /*2
<span>NaBiO3 +6H⁺ +2e⁻ -----> Bi³⁺ + Na⁺ + 3H2O /*5
</span>2Mn²⁺ + 5 NaBiO3+8H2O+30H⁺ ---> 2MnO4⁻ +5Bi³⁺ + 5Na⁺ +16H⁺ +15H2O
</span>2Mn²⁺ + 5 NaBiO3+14H⁺ ---> 2MnO4⁻ +5Bi³⁺ + 5Na⁺ +7H2O
There are 7 water molecules in this reaction.
D. With the same number of protons and different number of neutrons.
