Year 8 Science · Unit 2 · Lesson 07
Foundation Worksheet
Learning Goals
Fill the gap
Choose the correct word from the word bank to complete the passage below. Each word is used once. Two words in the bank will not be used.
Every atom has a nucleus that contains two types of particles: and . The is the count of protons in the nucleus, and it always identifies which the atom belongs to. For example, any atom with 6 protons is always carbon, no matter what else is happening inside the nucleus. The is a larger number: it equals the total of protons plus neutrons. To find the number of neutrons, subtract the atomic number from the mass number. In a atom, the number of surrounding the nucleus always equals the number of protons.
Match each term to its definition
Write the letter of the correct definition next to each term in the "Your answer" column. Each letter is used once.
| Term | Your answer | Definition |
|---|---|---|
| Atomic number | A. The total number of protons and neutrons in the nucleus. | |
| Mass number | B. Found by subtracting the atomic number from the mass number (A − Z). | |
| Number of neutrons | C. The number of protons in the nucleus of an atom. | |
| Number of electrons (neutral atom) | D. Written with mass number at top-left and atomic number at bottom-left of the element symbol. | |
| Element identity | E. Always equal to the number of protons in a neutral atom. | |
| Nuclear symbol | F. Determined solely by the atomic number, change it and you change the element. |
1. State the difference between atomic number and mass number. Use the terms "protons" and "neutrons" in your answer.
2. The nuclear symbol for aluminium is ²⁷₁₃Al. Identify the atomic number and mass number of this atom, and calculate the number of neutrons it contains.
Wrap Up
In one sentence, what was the main idea of this lesson?