The correct statement is
- Aluminium has five valence orbitals.
- Boron has a maximum covalency of four.
- Beryllium has three valence orbitals.
- Magnesium has a maximum covalency of four.
Previous year questions with solutions · 2000 – 2026
| Year | Questions | Papers | Avg / paper | Weightage |
|---|---|---|---|---|
| 2026 | 2 | 2 | 1 | 2.22% ↓43.3% |
| 2023 | 2 | 1 | 2 | 3.92% ↓1% |
| 2022 | 4 | 2 | 2 | 3.96% ↑78.2% |
| 2020 | 1 | 1 | 1 | 2.22% ↓50% |
| 2019 | 2 | 1 | 2 | 4.44% →0% |
| 2018 | 2 | 1 | 2 | 4.44% ↑100% |
| 2017 | 1 | 1 | 1 | 2.22% →0% |
| 2016 | 2 | 2 | 1 | 2.22% ↑100% |
| 2015 | 1 | 2 | 0.5 | 1.11% ↓80.2% |
| 2013 | 5 | 2 | 2.5 | 5.62% ↑355.1% |
| 2011 | 1 | 2 | 0.5 | 1.23% ↓1.2% |
| 2010 | 1 | 2 | 0.5 | 1.25% ↓68.1% |
| 2009 | 2 | 1 | 2 | 3.92% ↓2% |
| 2007 | 2 | 1 | 2 | 4.00% ↑92% |
| 2004 | 1 | 1 | 1 | 2.08% ↑2.1% |
| 2003 | 1 | 1 | 1 | 2.04% ↑4.1% |
| 2001 | 1 | 1 | 1 | 1.96% →0% |
| 2000 | 1 | 1 | 1 | 1.96% |
⚠ 1 of these questions are out of the current syllabus (marked on the question).
The correct statement is
Taking stability as the factor, which one of the following represents correct relationship?
Which of the following statements is not correct about diborane?
Na2B4O7 heat X + NaBO2 in the above reaction the product "X" is :
The correct order of atomic radii in group 13 elements is
Which one of the following elements is unable to form MF63- ion?
Boric acid is an acid because its molecule
AlF3 is soluble in HF only in presence of KF. It is due to the formation of
The stability of +1 oxidation state among Al, Ga, In and Tl increases in the sequence
Which of the following is electron-deficient ?
Which of the following structure is similar to graphite?
The tendency of BF3, BCl3 and BBr3 to behave as Lewis acid decreases in the sequence
The stability of +1 oxidation state among Al, Ga, In and Tl increases in the sequence
Which one of the following compounds is not a protonic acid?
Which compound is electron deficient?