Which contribution added to Rutherford's discovery of a positive nucleus?
a) Atoms are indivisible.
b) Electrons are scattered in an atom.
c) Neutrons are inside the nucleus of an atom.
d) Atoms of the same element have the same properties.
c) Neutrons are inside the nucleus of an atom.
Which of the following elements has the highest atomic mass?
a) Helium: 2 protons and 2 neutrons
b) Nitrogen: 7 protons and 7 neutrons
c) Oxygen: 8 protons and 8 neutrons
d) Hydrogen: 1 proton and no neutrons
b) Nitrogen: 7 protons and 7 neutrons
Match the scientist to his contribution to the atomic theory.
Match Term Definition
J. J. Thomson A) Electrons are scattered within the atom.
John Dalton B) Electrons are in orbital levels.
Ernest Rutherford C) Atoms are the smallest unit of an element.
Niels Bohr D) Protons are at the center of an atom.
Match Term Definition
J. J. Thomson A) Electrons are scattered within the atom.
John Dalton B) Atoms are the smallest unit of an element.
Ernest Rutherford D) Protons are at the center of an atom.
Niels Bohr C) Electrons are in orbital levels.
There are equal numbers of protons and electrons in neutral atoms.
True
False
True
Fill in the blank
A neutral atom of helium has 2 protons and ______ electrons. (Enter a whole number.)
Numerical Answers Expected!
2.
Which of the following statements does not describe the structure of an atom?
a) An atom has a small, dense center called the nucleus.
b) Inside the nucleus of an atom are protons and electrons.
c) Protons are positively charged sub-atomic particles.
d) Electrons are negatively charged sub-atomic particles.