Periodic Classification of Elements Test - 5

Newlands' method of classification of elements was known as law of octaves because every eighth element had the properties similar to the first.

According to Newlands' law of octaves, every eighth element had the properties similar to the first. Thus, properties of beryllium resembles those of magnesium.

Mendeleev placed the elements in the increasing order of their atomic masses, but cobalt was placed before nickel even though it has a higher atomic mass than nickel.

Properties of gallium were similar to that of eka-Aluminium.

Helium (He) has the highest ionisation energy because, like other noble gases, helium's valence shell is full. Therefore, helium is stable and does not readily lose or gain electrons.

Protium is the most common isotope with a relative abundance of 99.98%, followed by deuterium (0.0026–0.184%) and tritium.

Noble gases are so called because they exhibit chemical inertness.

In the given electronic configuration, the last element enters in p-orbital. Thus, it is a p-block element.

In the periodic table, elements are arranged in the increasing order of their atomic numbers. Thus, the correct increasing order of the given elements is hydrogen, helium, lithium and boron

Calcium is a chemical element with symbol Ca and atomic number 20. Thus, electronic configuration of calcium is 2, 8, 8, 2.