atomic structure Flashcards
(26 cards)
What is an element?
A substance which contains only one TYPE of atom.
What is a compound?
A substance which contains two or more types of atom bonded together.
What are mixtures?
Different elements or compounds that can be separated as they are not chemically bonded together.
What are the starting materials in chemical reactions called?
Reactants.
What are the four state symbols used in chemistry?
- (s) = solid
- (l) = liquid
- (g) = gas
- (aq) = aqueous (dissolved in solution)
How do you separate an insoluble solid from a solution?
By filtering it out.
How do you separate a salt from a solution?
Evaporate the water to produce crystals of salt.
What method is used to separate and collect a liquid from a mixture?
Distillation.
What are the three subatomic particles?
- Protons
- Electrons
- Neutrons
What is the charge and relative mass of protons?
Positive (relative charge is +1) and have a relative mass of 1.
What is the charge and relative mass of electrons?
Negative (relative charge is -1) and their relative mass is very small.
What is the charge and relative mass of neutrons?
Neutral (relative charge is 0) and have a relative mass of 1.
Where are protons and neutrons found in an atom?
In the nucleus.
What is the overall charge of atoms and why?
Atoms have no overall charge because the number of positive protons is equal to the number of negative electrons.
What does the atomic number represent?
The number of protons.
What does the mass number represent?
The number of protons and neutrons in total.
What are atoms of the same element with different numbers of neutrons called?
Isotopes.
How are electrons arranged in an atom?
In energy levels (shells).
What is the maximum number of electrons in the first three energy levels?
- 2 in the first
- 8 in the second
- 8 in the third
What is the electronic structure of sodium with 11 electrons?
2,8,1.
What did Dalton believe about atoms?
Atoms were hard spheres and that elements had only one type of atom.
What did J.J. Thompson discover?
The electron, describing atoms like ‘plum puddings’ with negative charges embedded in a cloud of positive charge.
What did Geiger and Marsden’s experiments show?
Atoms could not be solid.
What is the nuclear model proposed by Rutherford?
The positive charge of an atom is in a small centre called the nucleus, with electrons orbiting this nucleus.
