Protons, neutrons and electrons
Grade 8 Science Worksheet - Challenge Me
Circle the best answer, or write your answer on the line.
Ari reads that an iron atom has mass number 56 and 30 neutrons. How many protons does it have?
Bo reads that a copper atom has mass number 63 and 34 neutrons. How many protons does it have?
Esme reads that a boron atom has mass number 11 and 6 neutrons. How many protons does it have?
Jun says electrons sit inside the nucleus, next to the protons. Agree or disagree?
- Agree: opposite charges sit together
- Agree: the nucleus holds the whole atom
- Disagree: electrons are outside the whole atom
- Disagree: electrons are around the nucleus
Kira says a neutron has a small positive charge. Agree or disagree?
- Disagree: it is negative
- Agree: it is a weak proton
- Agree: it sits with the protons
- Disagree: it has no charge
Luz says an electron has about the same mass as a proton, since their charges balance. Agree or disagree?
- Agree: equal charges mean equal mass
- Disagree: an electron is far lighter
- Disagree: an electron is heavier
- Agree: both are particles in one atom
Atomic number, symbol, name. 5 B boron; 6 C carbon; 7 N nitrogen; 8 O oxygen. A carbon atom has 6 protons and 6 neutrons. If it had one more neutron, what would it be, Milo?
- Nitrogen, the next element
- Oxygen
- Still carbon, with mass number 13
- Boron, since it is heavier
Atomic number, symbol, name. 16 S sulfur; 17 Cl chlorine; 19 K potassium. Atom X has 17 protons and 18 neutrons. Atom Y has 17 protons and 20 neutrons. What are they, Pia?
- Two different elements, since neutrons differ
- Both sulfur
- X is chlorine and Y is potassium
- Both chlorine
Ren checks three classmates' atom models. Which one is right?
- Protons and neutrons in the center, electrons around
- Electrons drawn inside the nucleus
- Neutrons marked −, electrons marked +
- Particles spread evenly through the atom
A model shows a tiny nucleus and a wide cloud of electrons. Where is most of the mass, Zee?
- Shared evenly, since everything counts the same
- Nowhere: atoms are empty
- In the tiny nucleus
- In the wide electron cloud