Structure of the Atom Flashcards
What charge do electrons have?
Negative (-1)
What charge do protons have?
Positive (+1)
What charge do neutrons have?
Neutral (0)
Where are electrons found in an atom?
In the shell
The group number tells you…
how many electrons are in the outer shell.
The period number tells you…
how many shells the atom has.
Ionic bonding is between what?
Metal + Non-metal
Covalent bonding (sharing bonding) is between what?
Non-metal + Non-metal
Compound
A substance made from two or more different elements that have been chemically joined
What did Dalton say about atoms in 1803?
All matter is made of atoms and atoms cannot be split
Describe Thompson’s Model (1897)
Plum Pudding Model
An atom is like a plum pudding:
A ball of positive charge (the dough) with negatively charged electrons (the currants) distributed randomly throughout
Define Alpha Particle
2 protons and 2 neutrons
Helium Nucleus
not needed - (Composite particle consisting of two protons and two neutrons tightly bound together)
Describe Rutherford’s nuclear model (1909)
Atom’s mass is concentrated at it’s centre
(Most of the atom is empty space)
This was called the nucleus and contained positively charged particles called protons
What did Niels Bohr discover about the atom?
Electrons orbit the nucleus at fixed distances
What did James Chadwick discover in 1932?
Neutrons
Some particles in the nucleus have no charge at all. He called them neutrons.
