Licuicy niculum
predict the missing component of each reaction
? + 2nabr → 2nacl+br
o hci
o ci)
o na
mg+? → mgo+h2
• mg(oh)2
o o₂
o h2o

Missing component

Cl₂

H₂O

Explanation:

Reaction given:

? + 2NaBr → 2NaCl+Br

Mg+? → MgO+H2

missing component = ?

Solution:

Reaction 1

             ? + 2NaBr → 2NaCl + Br

if we look at the reactants and products there is one element is in product side but not shown in the reactant side.

In products there are following atoms

Na (Sodium)

Cl (Chlorine)

Br (Bromine)

In Reactant there are following atoms

Na (Sodium)

Br (Bromine)

So only Chlorine is missing in the reactant side.

if we put chlorine in the reactant then this reaction will be complete

        Cl + 2 NaBr → 2NaCl + Br

So chlorine react with water and give sodium chloride and bromine molecule, this is a single displacement reaction and chlorine replace bromine in the above reaction

Now balance the equation

          Cl₂ + 2 NaBr → 2NaCl + Br₂

So, the missing component is

Reaction 2

                Mg + ? → MgO + H₂

if we look at the reactants and products there are two element in product side but not shown in the reactant side.

In products there are following atoms

Mg (Magnesium)

O (Oxygen)

H (Hydrogen)

In Reactant there is only one following atom

Mg (Magnesium)

So Oxygen and Hydrogen is missing in the reactant side.

if we put water molecule (H₂O) in the reactant then this reaction will be complete

          Mg + H₂O → MgO + H₂

in this reaction magnesium (Mg) react with water (H₂O) and give magnesium oxide and hydrogen gas.

So, the missing component is

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.