Question

an element X is having three shells and formula of its fluoride is XF3. What will be the position of X in periodic table​

Answer 1

Answer:

✭ Group 13 IIIA✭

Explanation:

The modern periodic table has 18 vertical columns, comprising of groups ( I to VIII and zero ).The groups I to VII a divided into sub-groups thereby making a total of 18 groups.

First of all we must know how we write a chemical formula or how the chemical formula is formed?

The following steps should be taken while attempting to write a formula..The method is called criss-cross method.

• Write the symbol.
• Then write the valency on the top of its symbol [Ignore the signs].
• Divide the valency by their highest common factor to get the simplest ratio.
• Interchange the valencies of these radicals.
• Write the interchange the valency number to the lower right of the radical.

Now,

❖ F is the element fluorine of group VIIA. It has 7 electrons in its valence shell, which means that it needs one more electron to complete its octet.

➤ An element X is having three shells and formula of its fluoride is XF₃ , which means that an element X is forming a compound with 3F's and it need to give electrons to each of the Fluorine element.

Let's see which element it is:

➲ Firstly, we considered group 1 these are alkali metals and first element is hydrogen, whose valency is 1 so if the element is hydrogen, the compound must be XF, thus considering hydrogen is wrong. It gives only 1 electron.

➲ Secondly, consider the second group alkaline earth metals whose first element is Beryllium, whose valency is 2 so if the element is beryllium, the compound must be XF₂ , thus considering beryllium is wrong. It gives only 2 electron.

➲ Thirdly, group 13 III-A - Boron family because first element of the group is boron, whose valency is 3 so if the element is boron, the compound must be XF₃ , thus considering beryllium is right. It gives only 3 electron.

∴ The element is Boron which belongs to Group 13 ✓

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