Question

Elements with an electron sextet are ________.

Answer 1

Hint- In order to deal with this question first we will define the term sextet of electron then for better understanding we will take a general example of the compound of that element which shows the sextet form of the element.

Complete answer:
In an element of a compound, when the number of electrons in the valence shell is equal to 6, it is called sextet of electrons.
The most common example is Boron halides, $B{X_3}$
Example: $B{F_3}$
Boron has the electronic configuration of $1{s^2}2{s^2}2{p^1}$ . It has 3 electrons in its outer shell. Thus in the compound $B{X_3}$ (where X is one of the halides), it bonds with three halide atoms to have a sextet of electrons.
Hence, element with an electron sextet are boron in $B{F_3}$

Additional information-
In chemistry, an element is a pure substance that can not be broken down by chemical means, composed of atoms and their atomic nuclei containing identical numbers of protons. An element's defining property is the number of protons in the nucleus, and is referred to as the atomic number. All of the baryonic matter of the universe is constituted by chemical elements.
A total of 118 elements were identified. The first 94 are naturally occurring on Earth, and the remaining 24 are synthetic elements created in nuclear reactions. Save for reactive radioactive elements (radionuclides) that rapidly degrade, almost all of the elements are industrially available in varying quantities.

Note- A "sextet" atom has a lack of electrons and is ready to fill the byte with 2 extra valence electrons. By a Lewis acid-base reaction (between ether and $B{F_3}$) or lone-pair donation from a neighbouring atom (the mesomeric structures of the two carbocations), another bond of two electrons is made to the sextet atom, and its octet is completed.