Question

Q12. Read the following and answer any four questions from 12(a) to 12(e)
The modern periodic table has 18 vertical columns known as groups and 7 horizontal rows known as period. Group 1 of modern periodic table contains the same number of valence electrons that is, 1. Similarly you will find that if the elements present in anyone group have the same number of valence electron for example elements fluorine and chlorine belong to group 17, and contain 7 electrons in their outermost shells. Hence, we can say that groups in the periodic table signify an identical outer shell electronic configuration. On the other hand, the number of cells increases as we go down the group. There is an anomaly when it comes to the position of hydrogen because it can be placed in group 1 or group 17 in the first period.

a) Where would you locate the element with electronic configuration 2, 8 in the modern periodic table? 1
1) Group 8.
2) Group 2.
3) Group 18.
4) Group 10.
b) Which of the given elements A, B, C and D with atomic number 2, 3, 7, and 10 respectively belong to the same period? 1
1) A &C.
2) A&D.
3) B&C.
4) B&D.

c) Which of the following statements is not a correct statement about the trends when going from left to right across the periods of periodic table? 1
1) The elements become less metallic in nature.
2) The number of valence electrons increases.
3) The atoms lose their electrons more easily.
4) The oxide becomes more acidic.

d) Which of the following statements about Modern Periodic table is correct? 1
1) The elements in the modern periodic table are arranged on the basis of their decreasing atomic number.
2) The elements in Modern Periodic table are arranged on the basis of their increasing atomic mass.
3) Isotopes are placed in adjoining groups in the periodic table.
4) The elements in the modern periodic table are arranged on the basis of their increasing atomic number.

e) Which of the following statements about Modern Periodic table is correct? 1
1) It has 18 horizontal rows known as periods.
2) It has 7 vertical columns known as periods.
3) It has 18 vertical columns known as groups.
4) It has 7 horizontal rows known as groups.

Answer 1

Answer:

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A chemical formula is an expression that shows the elements in a compound and the relative proportions of those elements. ... Molecular formulas do not indicate how the atoms are arranged in the molecule. The empirical formula tells the lowest whole-number ratio of elements in a compound.