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प्रश्न
The atomic numbers of four elements P, Q, R and S are 6, 8, 14 and 16 respectively. Out of these, the element known as metalloid is:
(a) P
(b) Q
(c) R
(d) S
उत्तर
(c) R.
R (Si) is a metalloid since its atomic number is 14 and it has 4 valence electrons.
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संबंधित प्रश्न
State modern periodic law.
The atomic numbers of the three elements X, Y and Z are 2, 6 and 10 respectively.
(i) Which two elements belong to the same group?
(ii) Which two elements belong to the same period?
Give reasons for your choice.
The elements A, B, C and D belong to groups 1, 2, 14 and 17 respectively of the periodic table. Which of the following pairs of elements would produce a covalent bond?
(i) A and D
(ii) C and D
(iii) A and B
(iv) B and C
(v) A and C
Name the type of elements which have outermost shell complete.
Write a short note.
Structure of the modern periodic table.
Which of the following statements about the Modern periodic table is correct?
An element X which is a yellow solid at room temperature shows catenation and allotropy. X forms two oxides which are also formed during the thermal decomposition of ferrous sulphate crystals and are the major air pollutants.
- Identify the element X
- Write the electronic configuration of X
- Write the balanced chemical equation for the thermal decomposition of ferrous sulphate crystals?
- What would be the nature (acidic/ basic) of oxides formed?
- Locate the position of the element in the Modern Periodic Table.
Define periods of modern periodic table.
What is the general name of the last elements of the Periodic Table?
An element has 2 electrons in its N shell.
Is it a metal or a non-metal?
