What is the radius of an atom? - correct answer ✔Around 10^-10m
What is the basic structure of an atom? - correct answer ✔A positively
charged nucleus composed of both protons and neutrons surrounded by
negatively charged electrons
What fraction of the atom is the radius of the nucleus? - correct answer
✔1/10,000th
Most of the mass of an atom... - correct answer ✔...is concentrated in the
nucleus
How can electron arrangements change in an atom? - correct answer ✔1.
Absorption of electromagnetic radiation - move further from nucleus; higher
energy level
2. Emission of electromagnetic radiation - closer to nucleus; lower energy
level
The number of protons in an atom is equal to... - correct answer ✔...the
number of electrons in the atom
What do all atoms of the same element have in common? - correct answer
✔They have the same number of protons
Mass number - correct answer ✔The total number of protons and neutrons
, How can atoms be represented? - correct answer ✔Mass number on top,
atomic number under
What happens if atoms lose one or more outer electrons? - correct answer
✔They turn into positive ions
Isotope - correct answer ✔An atom of the same element with a different
number of neutrons
What may lead to a scientific model being changed or replaced? - correct
answer ✔New scientific evidence
How has the atomic model developed? - correct answer ✔1. Tiny undivisible
spheres
2. Plum pudding model
3. Nuclear model
4. Bohr's nuclear model
5. Discovery of protons
6. Discovery of neutrons
Plum pudding model - correct answer ✔The atom is a ball of positive charge
with negative electrons embedded in it
Nuclear model (alpha scattering experiment) - correct answer ✔1. Most
particles went straight through - mostly empty space, nucleus small compared
to whole atom
2. Some particles deflected several degrees - nucleus positively charged as
positive particles were repelled