Question

Give the following information for the atom: [1] the atomic number; [2] the mass number; [3] the number of protons; [4] the number of neutrons; [5] the number of electrons.

Answer 1

The atomic number represents the number of protons, the mass number the sum of protons and neutrons, and for neutral atoms, the number of electrons equals the number of protons. Oxygen has an atomic number of 8 and a mass number of 16, potassium has an atomic number of 19 and a mass number of 39, and lithium has an atomic number of 3 and a mass number of 7.

Step-by-step explanation:

For an atom, several key pieces of information can be identified, such as atomic number, mass number, number of protons, neutrons, and electrons. Here, we can define these and provide the information for specific atoms:

• The atomic number is the number of protons in the nucleus of the atom and defines the identity of the element.
• The mass number is the total number of protons and neutrons in an atom's nucleus.
• The number of protons, in a neutral atom, equals the number of electrons, which is given by the atomic number.
• The number of neutrons can be calculated by subtracting the atomic number from the mass number.
• Isotopes are atoms with the same number of protons but a different number of neutrons.

Using the information given:

1. An oxygen atom with 8 protons and 8 neutrons has an atomic number of 8 and a mass number of 16. Its complete symbol is O-16.
2. A potassium atom with 19 protons and 20 neutrons has an atomic number of 19 and a mass number of 39. Its complete symbol is K-39.
3. A lithium atom with 3 protons and 4 neutrons has an atomic number of 3 and a mass number of 7. Its complete symbol is Li-7.

Each of these atoms has an equal number of protons and electrons, because they are electrically neutral:

• Oxygen has 8 electrons.
• Potassium has 19 electrons.
• Lithium has 3 electrons.