Question

isotopes have the same number of protons but a different number of ____________. 2 point this is why their masses are different. electrons neutrons phases protons in rutherfords gold foil experiment, some particles bounced back when they got too close 2 points to the nucleus because like charges ______. attract combine repel expand john dalton determined that atoms can be: * 2 points indivisible expanded divided solids

Explanation:

• First Question: Isotopes are atoms of the same element. Since the mass number \(A = Z + N\) (where \(Z\) is the number of protons and \(N\) is the number of neutrons), and they have the same \(Z\) (same element), the difference in mass comes from different \(N\) (neutrons). Electrons contribute almost nothing to the mass. Phases are states of matter (solid, liquid, gas) and not related to atomic mass differences. Protons are the same in isotopes.
• Second Question: In Rutherford's experiment, the nucleus is positively charged (due to protons). The particles (alpha - particles which are positively charged) that got too close to the nucleus bounced back because of the electrostatic repulsion between like charges (positive - positive). Opposite charges attract, combining and expanding are not relevant to the charge - based interaction here.
• Third Question: John Dalton's atomic theory proposed that atoms are indivisible. Later theories showed that atoms can be divided (into sub - atomic particles like protons, neutrons, and electrons), but Dalton's original idea was that atoms are the basic, indivisible units of matter. Expanded and solids are not concepts from Dalton's atomic theory about the divisibility of atoms.

Answer:

1. neutrons
2. repel
3. indivisible