1c - atomic structure Flashcards
what is the plum-pudding model?
The atom is a ball of positive charge with negative electrons in it.
what is the Bohr/nuclear model?
it says that electrons orbit the nucleus in energy
levels
Describe the structure of an atom
The atom has a central nucleus around it are electrons.
what are the relative masses and relative charges of the proton, neutron and electron?
Masses: 1, 1, very small
Charges: 1, 0 , -1
why are atoms electrically neutral?
They have the same number of electrons and protons
what is the name of the number of protons in the nucleus?
Atomic number
Atoms of the same element have the same number of which particle in the nucleus?
Protons
Where is the majority of mass of an atom?
The nucleus
What is the mass number?
The number of protons and neutrons in the nucleus.
How do you calculate the number of neutrons using mass number and atomic number?
no. neutrons = mass number - atomic number
What is an isotope?
Atoms of the same element that have a different number of neutrons.
What is the relative atomic
mass?
The average mass value of an atom, compared to 1/12 of the mass of a carbon-12 atom.
true or false:
atoms of the same elements have the same number of protons.
true
what is the atomic number?
the number of protons in the nucleus of an atom.
what does the mass number tell you?
the mass number is the number of protons and neutrons in the nucleus of an atom
which subatomic particles are in the nucleus of an atom?
protons and neutrons
what is a molecule?
a group of two or more atoms held together by chemical bonds
true or false?
atoms are made of subatomic particles
true.
these are protons, neutrons and electrons
how do you calculate the number of electrons in an atom?
number of protons/the atomic number
state two pieces of info needed to calculate the relative atomic mass
- mass numbers of each isotope
- (relative/percentage) abundances of each isotope.
true or false?
the relative atomic mass of an element can be calculated using the atomic numbers and relative abundances of all its isotopes
false:
it is calculated using the mass numbers
in terms of isotopes, what is abundance?
the amount of each isotope present in a sample of an element
how can you recognise isotopes from their chemical symbol?
isotopes have the same symbol and same atomic numbers but different mass numbers
