Structure of Atoms
What is the center of an atom called?
Nucleus
Who proposed the first atomic theory?
Democritus
What makes up the majority of the mass of an atom?
Protons and neutrons
How is mass defined in terms of matter?
The amount of matter in an object
What is an isotope?
What is the main difference between an element and a compound?
An element is one type of atom; a compound is made of different types of atoms.
What is the name of John Dalton's atomic theory?
Solid Sphere Model
What does AMU stand for?
Atomis Mass Unit
What is the formula for calculating density?
density = mass / volume
What is an ion?
Atom that has an unequal number of protons and electrons
What are the three main subatomic particles of an atom, and what are their charges?
Protons (positive), neutrons (neutral), and electrons (negative)
What contribution did J.J. Thomson make to atomic theory?
The Plum Pudding Model- discovered electrons
What is the mass of a proton?
1 AMU
If an object has a mass of 20g and a volume of 5cm³, what is its density?
4 g/cm^3
What is the name of a positive ion? Negative ion?
Cation, Anion
What is the area around the nucleus called?
The electron cloud/ energy levels/ electron shells
How did Rutherford's gold foil experiment change the understanding of atomic structure?
He discovered that electrons move around the dense nucleus at the center. (Nuclear Model)
What is the overall charge of the nucleus in an atom?
Positive
How does the density of a substance change with temperature?
As substances increase in temperature, the density of the substance decreases (particles spread out)
What is the charge of an atom that has lost 3 electrons?
3+
What is the name of the force that keeps the negative electrons in orbit around the positive nucleus?
Electromagnetic force
What is the modern atomic theory?
Schrodinger's Model- Quantum Model
What role do neutrons play in the stability of an atom?
They keep the nucleus together using "strong force."
How would you measure the volume of a small rock? (must have the correct method name)
Water displacement
How can an atom become an ion?
Chemical reactions or static electricity