Isotopes and Neutron Counts
Written by Adi Ackerman, Head Teacher
"Isotopes and Neutron Counts" is written for 7th Grade (Ages 12-13). A 6th grader who is already steady on matter can use it too, and an older student can use it as a short review.
7th grade science worksheet: find protons and neutrons for isotopes like carbon-14 and uranium-235, then average atomic masses. Answer key included. Part of our atoms and molecules matter collection.
How do I use this worksheet?
Start with the guided notes or the Bohr model sheet to set vocabulary. Then assign the data table, isotope and formula sheets as practice, and use the history and scale sheets for reading and discussion.
What students will practice
- Students will find protons and neutrons for isotopes from atomic and mass numbers.
- Students will explain that isotopes of an element share the same protons.
- Students will calculate two average atomic masses and show their work.
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FAQ
How do I use this atoms and molecules worksheet?
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Start with the guided notes or the Bohr model sheet to set vocabulary. Then assign the data table, isotope and formula sheets as practice, and use the history and scale sheets for reading and discussion.
What does this worksheet teach?
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Find protons and neutrons for isotopes like carbon-14 and uranium-235, then average atomic masses. The directions on the page read: Fill in the table. Then find the two average atomic masses and show your work. An answer key is included.
Can I use this atoms and molecules worksheet for homeschool or classroom?
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Yes, both. We made it for 7th grade matter, and it works the same at home or at school. At home, a student can work through it alone and then go over it with you, which shows quickly what is solid and what needs another look. In class it works as independent practice, homework or a warm-up, and you can print one copy or a full set.
What is the difference between an element and a compound?
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An element has one kind of atom and a compound has two or more kinds joined together. On the formula sheet, students sort formulas such as O3 and CO and count the total atoms in each.
How do students find protons, neutrons and electrons?
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They use atomic number for protons and mass number minus atomic number for neutrons. In a neutral atom, electrons equal protons, and an ion's charge shows how many electrons were lost or gained.
Do the sheets cover how the model of the atom changed?
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Yes. One sheet places Dalton, Thomson, Rutherford and later models on a timeline and links each change to the evidence that caused it.
How small is an atom on these worksheets?
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A small atom is about 0.1 nanometer across, and a hair is about 0.1 millimeter wide. Students convert units and calculate how many atoms would span a hair.
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