Question

Which of the following is the best definition of an element?

A. chemical substance whose atoms all have the same number of protons
B. chemical substance that has lost or gained electrons
C. chemical substance made up of different types of atoms
Which of the following is the best definition of an element?
A. chemical substance whose atoms all have the same number of protons
B. chemical substance that has lost or gained electrons
C. chemical substance made up of different types of atoms

Answer 1

An element is defined as a chemical substance whose atoms all have the same number of protons. It is the simplest form of a chemical substance and has a unique set of physical and chemical properties.

Step-by-step explanation:

The best definition of an element is A. a chemical substance whose atoms all have the same number of protons. An element is the simplest form of a chemical substance, and it cannot be broken down into simpler substances by ordinary chemical means. Each element is unique because it contains only one type of atom, distinguished by a specific number of protons in its nucleus, which is known as the atomic number. For example, the element hydrogen has one proton, carbon has six protons, and gold has 79 protons.

The characteristics that define an element include:

• An element has a unique set of physical and chemical properties.
• An element's atomic number is equal to the number of protons in the nuclei of any of its atoms.
• The smallest unit of an element is the atom which retains all the chemical properties of that element.

Answer 2

A. chemical substance whose atoms all have the same number of protons

Step-by-step explanation:

An element is a substance which contains identical atoms that have the same number of protons in the nucleus.

Elements are arranged in the periodic table according to their atomic number (= number of protons): so atoms of different elements have a different number of protons in their nuclei.

For a neutral atom, the number of electrons around the nucleus is also equal to the number of protons.

Moreover, atoms of the same element can have a different number of neutrons, despite having the same number of protons - these atoms are called isotopes.