atomic structure Flashcards
what are all elements made of?
- atoms
what are atoms?
- the smallest part of an element that can exist
what are atoms made of?
- three types of subatomic particles
- protons, neutrons and electrons
what do electrons have?
(-1) charge
what do electrons do?
- wizz around the nucleus in orbitals, which take up most of the volume of the atom
where is most of the mass of the atom concentrated?
- in the nucleus
what is the nucleus?
- where you find the protons and neutrons
why is relative mass and relative charge used?
- because the mass and charge of the subatomic particles is really small
what is the relative mass of a proton?
1
what is the relative mass of a neutron?
1
what is the relative mass of an electron?
1/1840
what is the relative charge of a proton?
+1
what is the relative charge of a neutron?
0
what is the relative charge of an electron?
-1
why is the mass of the electrons not included when calculating the mass of the atom?
- the mass of electrons is negligible compared to the mass of protons and neutrons
what can you use to figure out the number of protons, neutrons and electrons in an atom?
- the nuclear symbol
what is the mass number?
- the total number of protons and neutrons in the nucleus of an atom
what is the atomic proton number?
- the number of protons (and electrons) in the atom
- it identifies the element
- all atoms of the same element have the same number of protons
why is the atomic number sometimes left out of the nuclear symbol?
- you don’t really need it because the element’s symbol tells you its value
what happens for neutral atoms which have no overall charge?
- the number of electrons is the same as the number of protons
how do you work out the number of neutrons?
mass number - atomic number (top - bottom in the nuclear symbol)
how do atoms form ions?
- by gaining or losing electrons
what do ions have?
- different numbers of protons and electrons
what do negative ions have?
- more electrons than protons
what do positive ions have?
- fewer electrons than protons
what are isotopes?
- atoms with the same number of protons but different number of neutrons
what decides the chemical properties of an element?
- the number and arrangement of electrons
why do isotopes have the same chemical properties?
- they have the same configuration of electrons
why do isotopes have slightly different physical properties?
- because physical properties depend more on the mass of the atom
