[Indranil (OP)]

'Mg + 0.5 O2 = MgO"
1. Is here 1 mole of O atoms in the product = 0.5 moles of O atoms  + 0.5 moles of O atoms in the reactant?
'2Mg + O2 = 2MgO
2. is 2  moles of O atoms in the product = 1 mole of O atoms + 1 mole of O atoms = 1 mole of O2 molecules?

[Kryptid]

A "mole" is just a way of quantifying a substance. It's analogous to saying a "dozen". So a mole of O₂ contains 2 moles of O.

[Indranil (OP)]

'Mg + 0.5 O2 = MgO"
1. Is here 1 mole of O atoms in the product = 0.5 moles of O atoms  + 0.5 moles of O atoms in the reactant?
'2Mg + O2 = 2MgO
2. is 2  moles of O atoms in the product = 1 mole of O atoms + 1 mole of O atoms = 1 mole of O2 molecules?

I mean If I split the
1. 'Mg + 0.5 O2 = MgO" to here 1 mole of O atoms in the product = 0.5 moles of O atoms  + 0.5 moles of O atoms in the reactant' Is it correct?
Same question for the second one
2.  '2Mg + O2 = 2MgO to '2  moles of O atoms in the product = 1 mole of O atoms + 1 mole of O atoms = 1 mole of O2 molecules' is it correct?

[Kryptid]

(1) I don't know why you say 0.5 + 0.5 moles of oxygen atoms. It's easier to just call it 1 mole in both the reactants and the product.
(2) I don't know why you say 1 + 1 moles of oxygen atoms. It's easier just to call it 2 moles of oxygen atoms in both the reactants and the product.

[Indranil (OP)]

(1) I don't know why you say 0.5 + 0.5 moles of oxygen atoms. It's easier to just call it 1 mole in both the reactants and the product.
(2) I don't know why you say 1 + 1 moles of oxygen atoms. It's easier just to call it 2 moles of oxygen atoms in both the reactants and the product.

Please see the two equations below and clear my doubts, please
1,  'Mg + 0.5 O2 = MgO"
2. 2Mg + O2 = 2MgO
My questions are
1. How many moles of O atoms combine to form 1 mole of O2 molecule?
2. How many moles of O atoms combine to form 1 mole of O atoms?
3. How many moles of O2 molecules form 2 moles of O atoms in the product?

[Kryptid]

Please see the two equations below and clear my doubts, please
1,  'Mg + 0.5 O2 = MgO"
2. 2Mg + O2 = 2MgO
My questions are
1. How many moles of O atoms combine to form 1 mole of O2 molecule?
2. How many moles of O atoms combine to form 1 mole of O atoms?
3. How many moles of O2 molecules form 2 moles of O atoms in the product?

(1) Two.
(2) Nothing is changing, so one.
(3) One.

[Indranil (OP)]

Please see the two equations below and clear my doubts, please
1,  'Mg + 0.5 O2 = MgO"
2. 2Mg + O2 = 2MgO
My questions are
1. How many moles of O atoms combine to form 1 mole of O2 molecule?
2. How many moles of O atoms combine to form 1 mole of O atoms?
3. How many moles of O2 molecules form 2 moles of O atoms in the product?

(1) Two.
(2) Nothing is changing, so one.
(3) One.

I forgot to ask one more questions, please see below:
4. How many moles of O2 molecules combine to form 1 mole of O atoms?

[Kryptid]

I forgot to ask one more questions, please see below:
4. How many moles of O2 molecules combine to form 1 mole of O atoms?

(4) 0.5 moles.