Same chapter3 marksDifficulty: Medium
State three achievements and two defects of Mendeleev's periodic table.
The Periodic Table
3 marksDifficulty: Medium
How many periods and groups are there in the modern periodic table, and what does the period number of an element tell you?
Original Khojo Papers practice question — not from a past board paper.
Answer
There are seven periods and eighteen groups. The period number gives the number of shells in an atom of the element.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
The group number is related to the number of electrons in the outermost shell.
Related questions
From the same topic and chapter, at a similar level.
Same chapter3 marksDifficulty: Medium
An element X has an atomic number of 16. Write its electronic configuration, its group and period, and the formula of its compound with hydrogen.
The Periodic Table
Same chapter3 marksDifficulty: Medium
State two advantages of the modern periodic table over Mendeleev's table.
The Periodic Table
Same chapter3 marksDifficulty: Medium
An element has the electronic configuration 2, 8, 8, 2. State its atomic number, period and group.
The Periodic Table
Same chapter2 marksDifficulty: Easy
State Mendeleev's periodic law and the modern periodic law, and say why the law was changed.
The Periodic Table
Same subject3 marksDifficulty: Medium
Balance the equation: Al + H2SO4 → Al2(SO4)3 + H2
The Language of Chemistry