Atomic structure&models Flashcards
What two sub atomic particles make up the nucleus?
Protons
Neutrons
What is the relative mass of both protons and neutrons?
1
What is the relative mass of an electron?
1/2000
How do electrons move around the nucleus?
They whizz around on orbitals
What is the mass number?
Total number of protons and neutrons in the nucleus of an atom
What is the atomic number?
The total number of protons, which also tells you the number of electrons
What is an ion?
When an atom loses of gains electrons, an ion is formed.
This causes a positive or negative charge
When forming an ion, how can you tell what the charge of the ion will become?
The group that the element is in will tell you how many electrons it must lose or gain to form a full outer shell
What is an isotope?
A variation of an element with the same number of protons but a different number of neutrons, resulting in a different mass but the same atomic number
Why do isotopes have the same chemical properties?
They have the same configuration of electrons
What was Daltons model of the atom?
He described atoms as solid spheres and said that different spheres made up the different elements
What was Thompsons model of the atom called?
The plum pudding model
What did Thompson conclude from his experiments?
That an atom must contain even smaller, negatively charged particles called electrons
What did the plum pudding model look like?
Electrons surrounded by a positively charged ‘pudding’
In the Rutherford experiment, what did they fire at a thin sheet of gold?
alpha particles
