Atoms + Radiation Flashcards
(38 cards)
An atom has a small, ……………. charged nucleus surrounded by orbiting negatively charged …………….
- positively
- electrons.
where is most of the mass in an atom concentrated?
the nucleus
what does an atoms atomic number show?
the number of protons is possesses
where are protons found in the atom?
in the nucleus
what relative charge do protons have?
+1
what do all atoms of the same element have the same number of?
protons
what relative charge do electrons have?
-1
where are electrons found in the atom?
in fixed orbits around the nucleus
why do electrons, overall, have no electric charge?
because the number of negative electrons balances out the number of positive protons
where are neutrons found?
in the nucleus
what relative charge do neutrons have?
0
- they are neutral
What is the overall charge of the nucleus of an atom?
positive
What do we call a small, negatively charged particle that orbits an atom’s nucleus?
electron
How many types of sub-atomic particles are there in an atom?
3
what are the 3 sub-atomic particles?
- proton
- neutron
- electron
In what environment would the relative mass of an atom change?
mas is constant across all environments
what did Ernest Rutherford discover?
the nucleus
Electrons have fixed positions within atoms, called ……………….. or energy levels, which surround the nucleus.
shells
What can be emitted by atoms to change the electron arrangement in an atom?
radiation
What happens when atoms absorb electromagnetic radiation?
electrons move to an energy level further away from the nucleus
Why would the alpha particles be deflected by a smaller angle if the thin metal foil was made of a lighter element?
The nuclei of lighter elements contain fewer protons. This means they have a lower charge. Each alpha particle will therefore experience a smaller electric force acting on it and so deflect by a smaller angle.
What is the nucleon number?
the total number of protons and neutrons in an atoms nucleus
what happens when an atom becomes charged by gaining or losing electrons?
it becomes an ion
Ions are ………. particles that form when an atom either loses or gains electrons.
charged