H2O (water) has 2 hydrogen atoms and 1 oxygen atom.
You can simply subtract the atomic number from the mass number in order to find the number of neutrons.
Answer:
Barium<Strontium<Calcium <Magnesium< Beryllium
Explanation:
Electronegativity is defined as the ability of an atom in a bond to attract the shared electrons of the bond towards itself.
Electronegativity is a periodic trend that decreases down the group and increases across the period.
Hence, if i want to arrange Beryllium, Barium, Strontium, Magnesium, Calcium in order of increasing electronegativity, i will have;
Barium<Strontium<Calcium <Magnesium< Beryllium
Molar mass NaHCO₃ = 23 + 1 + 12 + 16 x 3 = 84 g/mol
1 mole ---------- 84 g
? mole ---------- 110 g
moles NaHCO₃ = 110 . 1 / 84
moles NaHCO₃ = 110 / 84
= 1.309 moles
hope this helps!