In an atom of an element there are a fixed number of electrons. If the total mass of electrons in 1 mole (6.022 x 1023) of atoms of a certain element is 18.65 mg, how many protons must there be in the nucleus of that atom? (mass of electron = 9.109 x 10–28 g).

No. of protons = 34

Explanation:

First we need to calculate the number of electrons in one mole of the the element:

No. of electrons per mole = Total Mass of Electrons/Mass of 1 Electron

No. of electrons per mole = (18.65 x 10⁻³ g)/(9.109 x 10⁻²⁸ g)

No. of electrons per mole = 2.04 x 10²⁵ electrons/mol

Now, we calculate the no. of electrons in 1 atom:

No. of electrons per atom = No. of Electrons per mole/No. of atoms per mole

No. of electrons per atom = (2.04 x 10²⁵ electrons/mol)/(6.022 x 10²³ atoms/mol)

No. of electrons per atom = 34 electrons/atom

Since, the no. of protons in a pure element are equal to the number of electrons. Therefore,

No. of protons = 34

explanation:

the largest database of organic compounds lists about 10 million substances, which include compounds originating from living organisms and those synthesized by chemists. the number of potential organic compounds has been estimated at 1060—an astronomically high number. the existence of so many organic molecules is a consequence of the ability of carbon atoms to form up to four strong bonds to other carbon atoms, resulting in chains and rings of many different sizes, shapes, and complexities. the simplest organic compounds contain only the elements carbon and hydrogen, and are called hydrocarbons. even though they are composed of only two types of atoms, there is a wide variety of hydrocarbons because they may consist of varying lengths of chains, branched chains, and rings of carbon atoms, or combinations of these structures. in addition, hydrocarbons may differ in the types of carbon-carbon bonds present in their molecules. many hydrocarbons are found in plants, animals, and their fossils; other hydrocarbons have been prepared in the laboratory. we use hydrocarbons every day, mainly as fuels, such as natural gas, acetylene, propane, butane, and the principal components of gasoline, diesel fuel, and heating oil. the familiar plastics polyethylene, polypropylene, and polystyrene are also hydrocarbons. we can distinguish several types of hydrocarbons by differences in the bonding between carbon atoms. this leads to differences in geometries and in the hybridization of the carbon orbitals.