atoms Flashcards
what are atoms
smallest functional units of matter that form all chemical substances. cannot be further broken down by ordinary chemical or physical means. each specific type of atom is a chemical element
what are the 3 types of subatomic particles
- protons
- neutrons
- electrons
which 2 subatomic particles contribute to mass
- protons
- neutrons
what is the number of protons
the identity number of the element
what is the number of neutrons
the isotopic identity
what is the number of electrons
the charge of the element
tell me about protons
- positive charge
- found in the nucleus
tell me about neutrons
- neutral charge
- found in nucleus
tell me about electrons
- negative charge
- found in orbitals
if the number of protons and electrons are equal, that means the atom has what
no net charge
the number of what subatomic particle can vary
neutrons
what is the atomic number
- number of protons
- number of electrons if the net charge is zero
what does the number of protons do
distinguish one element from another
what shape are s orbitals
spherical
what shape are p orbitals
propeller or dumbbell shape
what happens to the energy as you approach the outer orbitals
it is increasing
what orbitals are found in the first shell
1s
what orbitals are found in the second shell
2s, 1p
how many electrons are in each orbital
2
how many orbitals are found in the second shell
- 1 2s orbital
- 3 1p orbital
do electrons want to fill up orbitals
yes, electrons tend to pair up and fill orbitals
what is it called when there’s only one electron in an orbital
an unpaired electron
what’s the principle called which describes how orbitals are filled by electrons
the Aufbau principle
in the Aufbau principle, what does n represent
the number of shells (rows on the periodic table)
when filling orbitals, in which order do you fill them
lower energy -> higher energy
1s ->2s ->2p ->2p ->2p
if all the shells are full and it is a gas, what kind of gas is is
inert gas
if you have a number of electrons which will lead to an uneven number in the 2p orbitals, how do you spread out the electrons
space them out within the 2p orbitals
what happens in the excited-state carbon atom
there are four valance orbitals each bearing one electron (2s, 2px, 2py, and 2pz). Thus, the excited-state carbon atom can form 4 covalent bonds
electrons in the outer shell available to combine with other atoms are called what
valence electrons
if an element has 10 protons how many electrons are held in the second shell
8
an element has 10 protons, how many unpaired valence electrons does it have
0
what do elements in the same row have in common
the same number of shells
what do elements in the same column have in common
the same number of unpaired electrons
what 2 subatomic particles are nearly the same in mass
protons and neutrons
what does the atomic mass scale indicate
an atom’s ,ass relative to the mass of other atoms
the most common form of carbon has 6 protons and 6 neutrons. what is the atomic mass
12
what does a dalton measure
atomic mass
one Dalton equals ___ the mass of a carbon atom ore the mass of a hydrogen atom
1/12
because a dalton has the atomic mass of 1/12 a carbon atom, what is the atomic mass of carbon
12
what does a mole measure
one mole of any element contains the same number of atoms
what is avogadros number
6.022 x 10^23
what is an isotope
multiple forma of any element that differ in the number of neutrons
if carbon is an isotope represented as 14C and has 6 protons, how many neutrons does it have
8
what does it mean if an isotope is unstable
it is radioactive
what do radioactivity dear rates help biologists do
to date fossils
what do radioactive isotopes help biologists do
label and trace/follow molecules as they are used by cells
what 4 elements make up about 95% of the atoms in living organisms
- hydrogen
- oxygen
- carbon
- nitrogen
where do hydrogen and oxygen primarily occur
in water
where is nitrogen most often found
- proteins
- DNA
- RNA
what element is the building block of all living matter
carbon
