Question

1. apply: turn off show isotope notation. set protons to 3 and neutrons to 4. write this isotope using isotope notation. hand write in this space or click here to select edit to use the drawing tool. check your answer in the gizmo.

Explanation:

Step1: Recall isotope notation

Isotope notation is $\ce{_{Z}^{A}X}$, where $Z$ is the atomic number (number of protons) and $A$ is the mass - number (sum of protons and neutrons), and $X$ is the chemical symbol.

Step2: Determine the atomic number

The number of protons is 3. The element with atomic number 3 is lithium (Li), so $Z = 3$.

Step3: Calculate the mass - number

The number of neutrons is 4. The mass - number $A=$ number of protons+number of neutrons. So $A=3 + 4=7$.

Answer:

$\ce{_{3}^{7}Li}$