Consumer good. Consumer good, in economics, any tangible commodity produced and subsequently purchased to satisfy the current wants and perceived needs of the buyer. Consumer goods are divided into three categories: durable goods, nondurable goods, and services.
Helium is a chemical element with symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table. Its boiling and melting points are the lowest among all the elements. Helium is the second lightest element and is the second most abundant element in the observable universe, being present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined.
gen atom. The chemical and physical properties of a substance refer to measurable or observable qualities or attributes that are used to distin-guish between different substances. Chemical properties describe how a substance interacts with other matter. Sodium and potassium, for example, react with water, but aluminum and gold do not. Physical properties are descriptive characteristics of matter. Examples of physical properties include color, density, conductivity, and malleability. Every substance will have a unique set of chemical and physical properties that can be used to identify it, because every type of substance has a unique atomic composition. It is often challenging to determine the identity of an unknown substance based on its chemical and physical properties.