Science Midterm Chapter 9 Flashcards
Which Greek philosopher was noted for challenging the popular idea of matter, but was ignored for nearly 2,000 years?
Democritus
Which scientist revisited the idea of empty space making up much of matter and rejected the idea of earth, water, air, and fire?
Dalton
Atoms are very small; so small that you could easily fit up to ____________ carbon atoms on the period of this sentence.
7.5 trillion
Which scientist first proposed that atoms contain electrons which have a negative charge?
Thomson
Which scientist is noted for the discovery of the nucleus of the atom?
Rutherford
Which scientist proposed that electrons move in circular orbits around the nucleus?
Bohr
Which atomic model added the idea of the electron cloud?
Modern Model
Just as atoms are made of smaller parts, protons & neutrons are also made of smaller parts called ______.
quarks
If you know the number of protons you will also be able to determine the number of ______.
electrons
The number of protons in an atom determine that element’s ______.
atomic number
Atoms of the same element that have different numbers of neutrons are called _____.
isotopes
Carbon has 6 protons, and the isotope C-13 must have how many neutrons?
7
Why is the atomic mass number of most elements always written as a decimal number?
it is an average
Becquerel, Pierre and Marie Curie are noted for the accidental discovery of _____.
radioactivity
What type of ray does not contain particles, but they do contain a lot of energy?
gamma
