Atomic People
Who stated that atoms were solid, indestructible spheres?
John Dalton
This experiment helped in discovering electrons.
Cathode Ray Tube Experiment
The smallest particle in an atom.
Electrons
Isotopes of an element have different numbers of what?
Neutrons
6.022 x 1023 is also known as what number?
Avogadro's Number OR a mole
The individual that created the Plum Pudding model of the atom and introduced the idea of electrons.
J.J. Thomson
Gold Foil Experiment
How many protons & electrons
What physical property changes about isotopes of an element?
Their mass
What unit is molar mass measured in?
Grams
Who discovered the neutron in the nucleus of an atom?
James Chadwick
Besides helping to discover the positively charged nucleus, what else did Rutherford's experiment help us learn about an atom? (the answer is not protons...)
That atoms are mostly empty space
What is the mass of a proton?
1 amu
Why is atomic mass on the periodic table a decimal?
It's a weighted average of all the isotopes
When dividing numbers in scientific notation, what needs to be done with the exponents?
Subtract
Antoine Lavoisier described this law that mass cannot be created or destroyed during a chemical reaction.
Law of Conservation of Mass
What is it about neutrons that made them take the longest to be discovered?
They have no charge so didn't react to electricity
Where can each subatomic particle be found?
Protons & neutrons = nucleus
Electrons = cloud
What is the equation for calculating the average atomic mass of an element?
∑(isotope mass x abundance)
4.0 moles of Helium would have mass of how many grams?
16g
(4.0 mol x 4.00 g/1mol)
What are 2 contributions that John Dalton made to our understanding of an atom? (he had 5 total)
-Matter is made of tiny particles called atoms
-Atoms of the same element have the same mass
-Atoms can't be subdivided, created, or destroyed
-Atoms come together in set ratios to create compounds
-Atoms can combine, be separated, or rearranged during chemical reactions
How did the cathode ray behave in Thomson's Cathode Ray Tube Experiment?
It bent towards a positive charge (proved it was made of negative charges)
What is the mass of an electron?
1/1896 amu
What would be the average mass of Nitrogen is it's 3 isotopes are as follows: 20% N13, 65% N14, and 15% N15
13.95 amu
How many atoms are in 2.75 mol of hydrogen?
1.66 x 1024 atoms
2.75mol x (6.022x1023 atoms)/1mol = 16.5605x1023
-Corrected for sig figs & scientific notation