I think you mean ionic bond and not conic bond. The pair of elements that form an ionic bond are barium and chlorine.
Answer:K2X
Explanation: Valency can be defined as the combining power of an element. It is the valency that dictates the value an element will have when writing a chemical formula for its compound.
MgX is a compound of magnesium and an element X. The valency of magnesium in most of its compound is +2. Now for the 2 to have been absent in the chemical formula, this shows that the element X itself have a valency if -2 for the valencies of both to have canceled out.
Now considering the element potassium, it is an alkaline metal belonging to group 1 of the periodic table. Hence, it is expected that it has a valency of +1
Forming a compound with element X means there would be an exchange of valencies between the two. We have established that x has a valency of -2. The formula of the compound thus formed by exchanging the valencies of both element would be K2X
Answer:
volume is the amount of space something occupies
Explanation:
the answer is true the first one
Answer : The correct option is, (D) 
Explanation :
(A) 
This reaction is a double displacement reaction in which the cation and anion of two reactants are exchange their places to give two different products.
(B) 
This reaction is a decomposition reaction in which the larger molecule decomposes to give two or more products.
(C) 
This reaction is a neutralization reaction in which an acid and a base react to give a salt and water as a product.
(D) 
This reaction is a redox reaction in which the oxidation and reduction reaction occur simultaneously.
Oxidation reaction is the reaction in which a substance looses its electrons. In this oxidation state increases.
Reduction reaction is the reaction in which a substance gains electrons. In this oxidation state decreases.
In this reaction, magnesium shows oxidation due to change in oxidation number from (0) to (+2) and hydrogen shows reduction due to change in oxidation number from (-1) to (0).
Hence, the correct option is, (D)