EVERYDAY SCIENCE

Detailed explanation-1: -Mendeleev went even further. He corrected the known atomic masses of some elements and he used the patterns in his table to predict the properties of the elements he thought must exist but had yet to be discovered. He left blank spaces in his chart as placeholders to represent those unknown elements.

Detailed explanation-2: -Moseley’s contribution to the periodic table was that he arranged the elements in the periodic table according to atomic numbers. He realized his findings indicated that the identity of an element is how many protons it has. The number of protons represents the atomic number of an element.

Detailed explanation-3: -Mendeleev noticed when ordering the elements that there appeared to be some elements missing. When there wasn’t an element with properties that he expected, he left a gap in his table. Mendeleev predicted the atomic weights and properties of these yet-undiscovered elements.

Detailed explanation-4: -Chlorine, oxygen and silicon were included in Mendeleev’s periodic table. Germanium was discovered later which fit into the empty spaces left by Mendeleev and matched to the expected properties.