Chemistry · Periodic Classification Of Properties · NEET
A main group element is one whose last (differentiating) electron enters an s orbital or a p orbital. So the main group is just the s-block plus the p-block together. Another name for them is representative elements. Their outer configuration follows the pattern ns1-2 (s-block) or ns2 np1-6 (p-block). Groups 1, 2 and 13 to 18 are the main group.
A transition element is a d-block element. Its last electron goes into the (n-1)d subshell, one energy level below the outermost shell. So its configuration has a partly filled d subshell, roughly (n-1)d1-10 ns1-2. They sit in the middle of the table, groups 3 to 12. NEET tip: if you see a 'd' with electrons other than a completely full inert core, it is likely transition.
The d-block is the transition block, NOT main group. Only s-block and p-block are counted as main group. This is a very common NEET trap. If the electronic configuration shows the last electron filling a d orbital, the element is transition, not main group.
Yes. 'Main group elements' and 'representative elements' are two names for the exact same set: the s-block and p-block elements. If a question uses either term, treat them as identical. Hydrogen and helium are usually placed in the s-block main group.
Look at where the LAST electron lands. If it lands in an s orbital (like [Ne]3s1) or a p orbital (like [Kr]4d10 5s2 5p5), it is main group. If it lands in a d orbital (like [Ar]3d3 4s2), it is a transition element. If it lands in an f orbital (like [Rn]5f7 7s2), it is an inner-transition element (lanthanoid or actinoid).
[Ar]3d10 4s1 is copper (Cu). It is a d-block element, so it is a transition element, not main group. NEET writes it with 4s1 at the end to tempt you into calling it s-block main group. Always classify by the block the element belongs to, not only by the very last symbol written. A filled 3d10 plus 4s1 is still d-block chemistry.
The f-block (lanthanoids and actinoids) are called inner-transition elements. They are separate from both main group and transition. A config such as [Rn]5f0 6d2 7s2 is thorium, an actinoid, so it is neither main group nor a normal transition element for NEET counting.
Which among the following electronic configurations belong to main group elements? A. [Ne]3s1 B. [Ar]3d3 4s2 C. [Kr]4d10 5s2 5p5 D. [Ar]3d10 4s1 E. [Rn]5f0 6d2 7s2
The element Z = 114 has been discovered recently. It will belong to which family/group and electronic configuration?
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Groups 1 and 2 (the s-block) and groups 13 to 18 (the p-block). Together these are the main group, also called representative elements.
Groups 3 to 12, the d-block. Their last electron enters a (n-1)d subshell, so they show a partly filled d subshell in one of their common states.
No. Aluminium is [Ne]3s2 3p1, a p-block element, so it is a main group element.
Zinc is in the d-block by position, but its d subshell (3d10) is completely full in both Zn and Zn2+, so strictly it is often not counted as a typical transition metal. For simple block-based questions, NEET treats d-block position as transition; read the exact wording of the question.
Because it lies between the s-block metals and the p-block, forming a bridge (transition) in properties. Their partly filled d orbitals give variable oxidation states and coloured ions.
