Atoms (T1) Flashcards
Describe electrons..
Tiny particles found in shells orbiting the nucleus.
The carry a negative charge but have a much smaller mass than any other particles in an atom.
The majority of the time they are never found in the nucleus and it’s the only particle outside of it.
Explain why it is the electrons in outer shell that directly determine the chemical and physical properties of a substance..
Because the outer shell of an atom is the only part of an atom that can interact and bond with other atoms to form molecules.
What is the level of energy of an electron expressed as?
-1
In an atom the number of protons =
The number of electrons
What is the charge of a proton expressed as?
+1
Describe protons..
The mass of a proton is much larger than an electron.
A proton is always positive and always found in the nucleus.
Describe neutrons..
Only found in the nucleus and have no charge.
How is the charge of a neutron expressed?
0
What is the mass of a proton expressed as?
1
What is the mass of a neutron expressed as?
1
How is the mass of an electron expressed?
0
What are the particles in the nucleus of an atom called?
Nucleons
What is the atomic number?
The number of protons in the nucleus of an atom.
What is the mass number?
The number of protons and neutrons in the nucleus.
What is an isotope?
Atoms of an elements that have different numbers of neutrons.
What are the three major particles of an atom?
- electrons
- protons
- neutrons
What are the electronic sub shells and the electronic capacities?
The shells of an atom divide sub-divide into sub shells known as s, p, d and f.
Their electronic capacities are:
s - 2
p - 6
d - 10
f - 14
Describe Bohr’s energy levels..
Low energy levels: closer to nucleus
High energy levels: further from nucleus
Ground state: electron in lowest energy level possible
What is an excited atom?
An atom that has absorbed energy.
The excited state is unstable.
The atom soon emits the same amount of energy absorbed.
The energy is seen as visible light.
What is the name of the region of space where an electron is likely to be found?
The orbital
