Question

chemistry:earth sys a: term af- period 2 - rm c202 (lms) quiz: modeling atoms (lms graded) there are neutrons in this lithium atom. review progress

Explanation:

Step1: Identify lithium's atomic number

Lithium (Li) has an atomic number of 3, which means it has 3 protons. In the image, the number of positive - charged particles (protons) is 3.

Step2: Determine the mass number

The mass number of a common lithium - 7 isotope is 7. The mass number is the sum of protons and neutrons in the nucleus of an atom.

Step3: Calculate the number of neutrons

Use the formula: Number of neutrons=Mass number - Number of protons. For lithium - 7, with 3 protons, the number of neutrons is 7 - 3 = 4.

Answer:

4