Lexi asked in Science & MathematicsPhysics · 5 years ago

Three Physics Questions Help?

I have a discussion based assessment tonight and i can't find my notes for these three questions, so if you could sort of help me understand the, that'd be awesome.

1. How does the kinetic energy (movement) of atoms or molecules change as they are heated or cooled?

2. How many protons, neutrons or electrons are in each atom? Be prepared to use the periodic table to tell me the number of each. (Ex. Lithium: Atomic #3, Atomic Mass: 7. It has 3 protons, 4 neutrons and 3 electrons)

3. How would you be able to identify two elements that have similar properties? (like the ability to bond). Example: What other elements would have similar properties to oxygen (O)?


This is a 9th grade physics question

1 Answer

  • 5 years ago
    Favorite Answer

    1. If you heat a molecule the kinetic energy goes up. The actual meaning of temperature is how fast molecules move, thus how much kinetic energy they have. If you cool them down, the kinetic energy becomes less as well.

    2. The periodic table is based on protons. So, atom #1 has 1 proton, #2 has 2, #3 has 3 etc. Isomeres have different neutrons depending on which isomere it is. Because of this, you won't always know how many neutrons a substance has, unless you have the mass. Both neutrons and protons have about 1,0u mass, and electrons have that small of a mass you can just pretend they're not there. This way you can tell how many neutrons a certain atom has; for instance Fe has number 26. This means it has 26 protons. The atomic mass is 55.8u. The amount of neutrons in it is 55-26=25. The amount of electrons is (normally) the same as the amount of protons. If you have the periodic table, you can actually tell this. The numbers on the bottom are the electrons, left top or bottom of the atom is the mass number, and right under or above it is the mass. The number before it is the atom number thus the number of protons.

    3. You'd have to do experments to see. You can heat them, solve them in water, let them react with different kinds of substances. You'll probably weigh the before/after to get a Δ m, or you time how long it takes to get a Δ s. This way you can compare the different substances.

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