Question

an atomic model for an element is shown below. based on the model, which statement correctly identifies the species represented? it is a lithium ion because it has 3 protons and a mass of 6. it is a lithium isotope because it has 3 protons and a mass of 7. it is a boron isotope because it has 5 protons. it is a lithium atom because it has 3 protons and 3 electrons.

Explanation:

Step1: Count protons

The nucleus has 3 protons. The atomic number of an element is determined by the number of protons. Lithium has an atomic - number of 3.

Step2: Count electrons

There are 3 electrons in the electron - shells. In a neutral atom, the number of protons equals the number of electrons.

Step3: Analyze the options

• Option 1: The mass number is not 6. There are 4 neutrons and 3 protons, so the mass number is 7. Also, it is not an ion as the number of protons equals the number of electrons.
• Option 2: It is not an isotope. An isotope has the same number of protons but different number of neutrons compared to the most common form. Here, it is a neutral atom.
• Option 3: There are 3 protons, not 5, so it is not boron.
• Option 4: It has 3 protons and 3 electrons, which makes it a neutral lithium atom.

Answer:

It is a lithium atom because it has 3 protons and 3 electrons.