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प्रश्न
How did the early chemists classify elements?
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उत्तर
Early chemists classified the elements on the bases of their properties, nature, character, valency, and whether they were metals or non-metals.
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संबंधित प्रश्न
An element P (atomic number 20) reacts with an element Q (atomic number 17) to form a compound. Answer the following questions giving reason:
Write the position of P and Q in the Modern Periodic Table and the molecular formula of the compound formed when P reacts with Q.
Why do we classify elements?
An element X combines with oxygen to form an oxide XO. This oxide is electrically conducting.
(a) How many electrons would be there in the outermost shell of the element X?
(b) To which group of the periodic tables does the element X belong?
(c) Write the formula of the compound formed when X reacts with chlorine.
An element X from group 2 reacts with element Y from group 16 of the periodic table.
(a) What is the formula of the compound formed?
(b) What is the nature of bond in the compound formed?
The non-metal A is an important constituent of our food and most of the fuels around us. A forms two oxides B and C. The oxide B is poisonous whereas oxide C causes global warming.
(a) Identify A, B and C.
(b) To which group of periodic table does A belong?
(c) Name another element which is placed in the same group as A.
Answer the following question.
Write the name, symbol, and electronic configuration of an element X whose atomic number is 11.
Which of the following have inert gases 2 electrons in the outermost shell.
Moseley’s periodic table is based on atomic mass.
Which one of the following statements is not correct about the trends in the properties of the elements of a group on going down in a group?
Identify and name the metals out of the following elements whose electronic configurations are given below.
- 2, 8, 2
- 2, 8, 1
- 2, 8, 7
- 2, 1
