Q.5 State 'True' or 'False', if 'False' correct it: 37
1) Newlands made groups of three elements each, having similar chemical properties and called them
triads.
2) Three of these unknown elements were given the names eka-boron, eka-aluminium and eka-silicon.
Later on these elements were discovered and named as scandium (Sc), gallium (Ga) and germanium
(Ge) respectively.
3) The groups 3 to 12 constitute the d-block, while the lanthanide and actinide series at the bottom form
the d-block.
4) Isotopes have similar chemical properties.
5) The elements in a group have consecutive atomic numbers.
6) Atomic radius is the distance between the nucleus of the atom and its outermost shell.
7) In the Indian music system there are seven main notes, namely, Sa, Re, Ga, Ma, Pa, Dha, Ni, and
their collection is called ‘Saptak’.
8) According to Modern periodic law, properties of elements are a periodic function of their atomic
numbers.
9) A zig-zagline can be drawn in the d-block of the periodic table.
10) Elements which are lie along the border of the zig-zag line are called as metalloids.
11) There was no place reserved for alkali metals in Mendeleev’s original periodic table.
12) The metalloid elements lie along the border of the zig-zag line.
13) The modern periodic table contains seven horizontal rows called the groups.
14) The number of shells increases down the group.
15) There are eight electrons in the outermost shell of the elements such as fluorine (F) and chlorine (Cl)
from the group 17.
16) Newlands fitted all the known elements in a table of 7 x 8 that is 56 boxes.
17) The d-block elements are called transition elements.
18) According to Mendeleev’s Periodic law, properties of elements are periodic function of their atomic
numbers.
19) Newlands arranged elements based on their atomic number.
20) According to Mendeleev, the previously determined atomic mass of beryllium, 14.09, was changed
to the correct value 9.4, and beryllium was placed before boron.
Answers
Explanation:
1.)False. Newlands proposed the idea of octaves whereas the idea of triads were given by Doberenier
2.)True
3.)False lanthanide and actinide are f block elements
4.) True
5.)False
6.)True
7.) True
8.)True
9.)True
10.)True
11.)False
12.)True
13.)False
14.) True
15.)False
17.)True
18.)False
19.)False
20.)False
ANSWERS
1) The given statement is false.
✳ Dobereiner made groups of three elements each, having similar chemical properties and called them triads.
2)The given statement is true.
3) The given statement is false.
✳ The groups 3 to 12 constitute the d-block, while the lanthanide and actinide series at the bottom form the f-block.
4) The given statement is true.
5) The given statement is false.
✳ The elements in a period have consecutive atomic numbers.
6) The given statement is true.
7) The given statement is true.
8) The given statement is true.
9) The given statement is true.
10) The given statement is true.
11) Statement is true the metalloids lie along the border of the zig-zag line.
12) The given statement is false.
✳ Alkali metals were reserved place in Mendeleev’s original periodic table.
13) The given statement is false.
✳ The modern periodic table contains seven horizontal rows called the periods.
14) The given statement is true.
15) The given statement is false.
✳ There are eight electrons in the outermost shell of the elements such as helium(He) and Neon(Ne) and form the group 18.
16) The given statement is true.
17) The given statement is true.
18) The given statement is False.
✳ According to Mendeleev’s Periodic law, properties of elements are periodic function of their atomic mass.
19) The given statement is False.
✳ Newlands arranged elements based on their atomic masses.
20) The given statement is true.