Chapter 1.7, Problem 4QQ

Interpretation Introduction

Interpretation:

Two most abundant element on Earth’s crust has to be chosen from the given options.

Concept Introduction:

Element is a pure substance and it cannot be broken down into simpler pure substance by chemical means like chemical reaction, electric current, heat, or light.  Over several centuries, the discovery of 118 known elements and its isolation have taken place.  These 118 elements are the building blocks of all matter.  Out of the 118 elements, eighty-eight elements are naturally occurring and the other 30 elements are laboratory synthesized by bombarding elements that naturally occur with small particles.

Elements that are laboratory synthesized are radioactive in nature and they convert back into the original naturally occurring element by emission of radiation.  All the elements that occur naturally are not evenly distributed on earth and universe.

Radiations that are emitted from stars can be used to estimate the elemental composition of universe.  This indicates that hydrogen and helium are mostly dominant.  On Earth’s crust oxygen and silicon are the two elements that account for about $80\%$ of the atoms which makes the chemical world of humans.