CIE Chemistry (US-0439): Specimen Questions with Answers 46 - 47 of 240

Question number: 46

MCQ▾

Question

What information can we gather about the elements present in a group of the modern periodic table when the group number is provided?

Choices

Choice (4) Response

a.

All the other options

b.

Valency of the elements

c.

Similar chemical properties

d.

Number of valence electrons

Answer

b.

Explanation

Correct option is B. In the modern periodic table, group number denotes the number of valence electrons present in that group.

As number of valence electrons is known so we can determine the valency of the elements.

As chemical properties of an element depend on the number of valence electrons so we can say that the elements present along a group have similar chemical properties.

For example, elements present in group have electrons in their valence shell.

So the valency of the elements is , i. e. 1.

As elements of group have valence electrons so they exhibit similar chemical properties.

Hence all the given choices are correct.

Question number: 47

MCQ▾

Question

Element X has six electrons in its outer shell. How could the element react?

Choices

Choice (4) Response

a.

By gaining two electrons to form a positive ion

b.

By losing six electrons to form a negative ion

c.

By sharing two electrons with two electrons from another element to form two covalent bonds

d.

By sharing two electrons with two electrons from another element to form four covalent bonds

Answer

a.

Explanation

Correct option is A (by gaining two electrons to form a positive ion) because X element represent , , , , and they all have six electrons in their outer most shell by Aufbau and they all gain two electron to form a positive ion. These elements are present under oxygen family as shown in figure.

Image of oxygen family in periodic table

Image of Oxygen Family in Periodic Table

Image of oxygen family in periodic table