Studied by 81 peopleatom
the smallest particle of an atom that still has the properties of that atom
What makes an atom neutral?
if there is the same number of protons and electrons
electron cloud
the space around the nucleus where the electrons orbit
electrons
negatively charged subatomic particles that help make up an atom
What determines which element an atom is?
the number of protons
neutrons
subatomic particles that do not have a charge
atomic number
the number of protons in an atom
mass number
the atomic mass of an atom (protons + neutrons)
1 amu =
1/12 of a carbon-12 atom
hyphen notation
name of the element - mass number of element
How are cations formed?
The atom loses electrons creating a positive charge
How are anions formed?
An atom gains electrons, creating a negative charge
What type of element generally forms cations?
Metals
What is the formula for atomic mass?
AMU= (mass A x A%) + (mass B x B%)
billard ball model
created by Democritius, the proposition that atoms existed
plum pudding model
created by jj thompson, discovered electrons
rutherford model
created by ernest rutherford, discovered that the middle of an atom was made up of a nucleus
Bohrs/Planetary Model
created by niels bohr, discovered electrons could jump between atoms by gaining or losing energy
The Quantum Mechanical model
created by multiple people, discovered the electrons moved in a fuzzy cloud and less of exact orbits
Who is attributed with the idea of arranging the known elements of his time into a model based on their chemical and physical properties?
Dmitri Mendelev
Who arranged the periodic table of elements by atomic number?
Henry Mosely
The periodic law states there is a periodic repetition of physical and chemical properties of the elements...
when they are arranged in order of increasing atomic number
valence electrons
electrons on the outer shell of an atom
What are the horizontal rows of the periodic table called?
periods
What do elements in the same periodic group have in common?
same valence configuration, same number of valence electrons, similar chemical properties
What do elements in the same periodic periods have in common?
same number of electron shells
What does PEL stand for?
Principal energy levels
How many elements are in the 2nd and 3rd rows of the periodic table?
eight
How many valence electrons do atoms in group 17 have?
7 or 17
What are the three classes of elements?
Metals, metalliods, non-metal
What elements are metalliods?
B, Si, As, Te, Ge, Sb
Which class of elements is dull, brittle, gains electrons, and are not good conductors?
non-metals
Which class of elements lose electrons, malleable, ductile, and are good conductors?
metals
most reactive group of nonmetals
17- halogens
completely unreactive periodic group
18- noble gases
which rows contain the transition metals?
3-12
most reactive group of metals
1- alkali metals
first row of the f-block elements
lathinides
class of elements that have both metal and nonmetal properties
metalliods
What is the periodic trend for atomic radius?
increases from left to right, increases down the group
What is the periodic trend for ionization energy?
increases from right to left across, increases up the group
What is the periodic trend for electronegativity?
increases from right to left across until the noble gases, increases up the group
what is ionization?
the amount of energy it takes to remove an electron from an atom
what is electronegativity?
the amount of attraction an element has to gaining electrons
Do metals have high or low electronegativity?
low
What element is most electronegative?
fluorine
Note
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