Question

who discovered the nucleus of an atom? * (0.5 points)
dalton
thompson
rutherford
chadwick
16
how many electrons are in the iron (iii) ion? * (0.5 points)
enter your answer
17
how many protons are in the uranium - 231 isotope? * (0.5 points)
enter your answer

Explanation:

Step1: Recall atom - nucleus discovery

Ernest Rutherford discovered the nucleus of an atom through his gold - foil experiment.

Step2: Determine electrons in iron(III) ion

Iron (Fe) has an atomic number of 26, meaning a neutral Fe atom has 26 electrons. An iron(III) ion ($Fe^{3 + }$) has lost 3 electrons. So, $26−3 = 23$ electrons.

Step3: Find protons in uranium - 231 isotope

The atomic number of uranium (U) is 92. The number of protons in an isotope is equal to its atomic number. So, uranium - 231 has 92 protons.

Answer:

1. C. Rutherford
2. 23
3. 92