Particle model of matter (Seneca) Flashcards
Atoms are very small and have a radius of about …
1 × 10-10 metres.
The electrons are arranged at different distances from the nucleus (————————).
different energy levels
The electrons are arranged at —————————— (different energy levels).
different distances from the nucleus
The radius of a nucleus is less than ————- of the radius of an atom.
1/10 000
Most of the mass of an atom is concentrated in the …
nucleus
Protons have a relative charge of …
+1.
An element’s atomic number is the …
number of protons it possesses.
All atoms of the ——- element have the same number of protons.
same
Electrons have a relative charge of …
-1.
Electrons are found in …
fixed orbits around the nucleus.
Neutrons have a relative charge of …
0
Ernest Rutherford discovered the nucleus by …
firing a beam of alpha particles at thin metal foils (only a few atoms wide).
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.
Each electron shell has a different ———- level.
energy
Electrons (negatively charged particles) have been shown to orbit the nucleus at ——— distances.
fixed
When an atom absorbs or emits electromagnetic radiation, its ————— can change.
electron arrangements
When atoms emit electromagnetic radiation, electrons move to a —————- the nucleus.
lower energy level, closer to
When atoms absorb electromagnetic radiation, electrons move to a ——————— the nucleus.
higher energy level further away from
When atoms ——- electromagnetic radiation, electrons move to a higher energy level further away from the nucleus.
absorb
When atoms ———-electromagnetic radiation, electrons can drop to a lower energy level, closer to the nucleus.
emit
What can be emitted by atoms to change the electron arrangement in an atom?
Radiation
Density (g/cm3) =
Mass(g) /volume (cm3)
The Law of Displacement says that …
an object completely submerged in a fluid (like water) will replace an amount of fluid equal to its own volume.
An object floats in a fluid if the density of the object is ——— than the density of the fluid.
lower