Atomic number is your answer.
The answer is number three because when electrons get excited they move up to the higher energy levels, and they emit light as the come back down to the lower quanta.
<span>Molten barium
chloride is separetes:</span><span>
BaCl</span>₂(l) →
Ba(l) + Cl₂(g), <span>
but first ionic bonds in this salt are separeted
because of heat:
BaCl</span>₂(l) →
Ba²⁺(l) + 2Cl⁻(l).
Reaction of reduction
at cathode(-): Ba²⁺(l) + 2e⁻ → Ba(l).
Reaction of oxidation
at anode(+): 2Cl⁻(l) → Cl₂(g) + 2e⁻.
The anode is positive
and the cathode is negative.
Pure substance - Ice cubes
Mixture - Homogenous sea water , lemonade
Pure substance are the substance which have constant chemical composition and characteristic.
Mixture is material made up of two or more chemical substance which are not chemical bonded. These materials in mixture are not in definite proportion.
As water ice cubes has only water in it thus it is pure substance.
Homogeneous sea water contains various salts and impurities in it thus it is mixture.
Lemonade contains lemon juice and water in it . Thus, it is mixture.
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