4.1 Parts of an Atom Flashcards
proton’s role
determines the identity of the atom
neutron’s role
holds together the nucleus
electron’s role
responsible for reactivity
proton’s charge
+1
neutron’s charge
0
electron’s charge
-1
proton’s mass
1 amu
electron’s mass
almost zero
neutron’s mass
1 amu
proton’s location
nucleus (proton)
neutron’s location
nucleus (neutron)
electron’s location
outside nucleus
most of the mass of the atom
comes from the nucleus
protons + neutrons
= mass number
the number of protons is also
the atomic number of an element
of protons - # of electrons
= charge
why don’t protons stick together?
they each have a +1 charge
why can’t an atom lose or gain a proton?
would change the identity of the atom
what is in the space between electrons?
nothing
empty space
when are atoms unstable?
when they have more or less neutrons or electrons than protons
what is a valence electron?
electrons in the outermost shell of an atom
what is most of the volume of an atom?
empty space outside the nucleus
An atom has 4 protons, 6 neutrons, and 5 electrons.
What is it’s charge?
it’s charge is -1
An atom has 4 protons, 6 neutrons, and 5 electrons.
What is it’s mass number?
mass number: 10
An atom has 4 protons, 6 neutrons, and 5 electrons.
What is it’s atomic number?
atomic number: 4
An atom has 4 protons, 6 neutrons, and 5 electrons.
How many valence electrons does it have?
3 valence electrons
what are isotopes?
atoms with the same number of protons but different numbers of neutrons
isotopes have the same atomic number but different
masses
isotopes react
similarly in chemical reactions
isotopes are often
unstable/radioactive
