Question

An element X (atomic number 17) reacts with an element 1 (atomic number 20) to form a divalent halide.
(a) Where in the periodic table are elements X and Y placed?
(b) Classify X and Y as metal (s), non-metal (s) or metalloid (s)
(c) What will be the nature of oxide of element Y? Identity the nature of bonding in the compound formed
(d) Draw the electron dot structure of the divalent halide

Answer 1

We can identify the elements using their atomic number. Their positions in the periodic table help to determine their chemical nature. We can say that electron dot structure is nothing but a representation of Lewis dot diagram of the valence electrons of an atom that uses dots around the symbol of the element.

Complete step by step solution:
The given data contains,
The atomic number of X is $17$.
The atomic number of ‘1’ is $20$.
From this information, we can predict the element X would be chlorine and the other element would be calcium.
(a) Chlorine is a halogen, and it belongs to the group $17$ and ${3^{rd}}$ period. Calcium belongs to group $2$ and ${4^{th}}$ period.
(b) We know that chlorine is gas and it is non-metal whereas calcium is alkaline earth metal. Chlorine is the p block element and calcium is the s block element.
Metal oxides would be basic, and oxides of nonmetals are generally acidic.
(c) Oxides of calcium are basic. The nature of calcium oxide is basic. The bond formed by calcium oxide is ionic bonding because calcium is metal and chlorine is non-metal. The bond formed between metal and non-metal is ionic bonding.
(d)We can give the electron dot structure of the divalent halide as,
We know that calcium has two outermost electrons and chlorine has seven valence electrons. Chlorine requires only one electron to fulfill its octet, whereas calcium has two electrons to lose. Thus, we need two atoms of chlorine to gain two electrons from one atom of calcium. We can give the transfer process as,

Note: We have to know that the calcium oxide is known as lime (or) quicklime. The chemical formula of calcium oxide is $CaO$. A salt is formed when calcium oxide reacts with acid. Calcium oxide is a stable compound and appears as an amorphous white solid that has a high melting point. Slaked lime is formed when calcium oxide is present in water.