Which describes elements in the first group of the periodic table? alkali metals alkaline earth metals transition metals radioactive metals

The correct answer is A. Alkali metals

Explanation:

The periodic table organizes and displays chemical elements in eighteenth groups according to the properties and features of the elements. The first group of elements is known as the Alkali metals; this group includes elements such as Potassium, Sodium, and Lithium. Additionally, these are classified as alkali metals because the elements of this group are highly reactive but soft metals, which are features other elements do not have. Thus, the elements in the first group are the Alkali metals.

answer; i believe that the correct answer is (d) a very small amount of mass

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.