Atomic Theory History
Ancient Greek who first discussed the concept of the atom. He did not have any scientific evidence to support his work.
Who is Democritus?
What is a proton?
A mol is an SI unit that describes the __________ of a substance.
What is the amount?
Two isotopes of the same element have ________ number of protons and ________ numbers of neutrons.
What are "the same" and "different"?
This is the atomic mass of a molecule of MgO, rounded to the nearest whole number.
What is 40?
This man is associated with the planetary model. He stated that electrons can only exist in certain energy levels.
Who is Niels Bohr?
This subatomic particle is negatively charged.
What is an electron?
Democritus's theory was revised for this reason.
What is it did not have a scientific basis?
An electron changes energy levels when it ___________.
What is gains or loses energy?
This many grams are in 8.36 moles of xenon (Xe.)
What is 1,100 g?
Dalton's theory was accepted for this reason.
What is he had scientific evidence that supported his theory.
This subatomic particle has no electrical charge/
What is a neutron?
The nucleus of an atom has this charge.
What is positive?
An atom's mass number tells us this about the atom.
What the number of protons and neutrons in the nucleus?
This many moles are in 46.5 grams of potassium (K).
What is 1.19 moles?
Thompson's work with cathode ray tubes led to the discovery of the __________.
What are electrons?
Atoms have no electrical charge for this reason.
What is they gave the same number of protons and neutrons?
A sodium atom has an atomic mass of 23. It has 11 protons and this many neutrons.
What is 12?
This is the subatomic particle with the least mass.
What are electrons?
This many grams are in 3.75 moles of magnesium (Mg.)
What is 91.1 g?
This man's gold foil experiment determined that there was a positive charge concentrated in the atom's center.
Who was Rutherford?
An atom's nucleus contains ___________.
What are protons and neutrons?
An element's atomic number is equal to the number of ________ it has.
What are protons?
Chlorine has this many valence electrons.
What is 7?
This many moles are in 225 g of nitrogen (N.)
What is 16.1 moles?