Ch2 redo Flashcards
Smallest particle of an element
Atom
Dalton’s atomic theory (4)
- Atoms are the most basic matter
particles that make up the elements
2.Atoms of the same elements are the same.
3.Atoms of one element cannot be chemically
changed into atoms of another element.
4.Atoms combined in whole number ratios can
describe compounds.
Discoverer of electron
JJ Thomson
Plum pudding model
by JJ Thomson, electrons in an positively charged sphere
Discoverer of proton
Ernest Rutherford
Gold foil experiment
Ernest Rutherford shot alpha particles at gold foil and noticed some were shot off at high angles
Rutherford’s nuclear model
nucleus of protons and neutrons, very dense
with a light and voluminous electron cloud
mostly empty space
Electron (symbol, charge, and mass)
e-
- 1
0. 000549 amu
Proton(symbol, charge, and mass)
p
+1
1.00728
Neutron(symbol, charge, and mass)
n
0
1.00867
Atomic number (Z)
number of protons in an element, lower left number when given.
Atomic mass (A)
number of protons plus neutrons, upper left number
Given in amu(atomic mass unit)
What are atoms of the same element but with different masses(due to differences in neutrons)?
isotopes
weighted average of atomic weights
mass of an isotope times its relative abundance plus the same for each isotope
Columns of periodic table are?
Groups, elements in the same group have similar chemical properties.
Rows of periodic table are?
Periods
Alkali metals are which group?
1A ex: Li
Alkaline earth metals are which group?
2A ex: Be
Chalcogens are which group?
6A ex: O
Halogens are which group?
7A ex: F
Noble gases are which group?
8A ex: He
Characteristics of metals
metallic shine (luster) conduct electricity well conduct heat well malleable ductile usually solid at room temp various reactivity loses electrons to form cations(positive) usually form ionic compounds
Characteristics of non-metals
poor electrical conductors poor heat conductors mostly found in compounds not malleable or ductile variable reactivity usually forming molecular compounds sharing of electrons) gain electrons to form anions(negative)
Subscript to the right of element symbol means?
the number of atoms of that element in one molecule of the compound.
molecular compounds
contains molecules usually of only nonmetals
Diatomic molecules (occur naturally as molecules with 2 atoms)
– Hydrogen – Nitrogen – Oxygen – Fluorine – Chlorine – Bromine – Iodine BrINClHOF
Which formulas give the lowest whole-number
ratio of atoms of each element in a compound?
Empirical formulas
Which formulas give the exact number of atoms
of each element in a compound?
Molecular formulas
Which formulas show the
order in which atoms are
bonded?
structural formulas
BLANK drawings also
show the three-dimensional
array of atoms in a compound.
Perspective drawings
An atom that gains or loses an electron is called an
When atoms lose or gain electrons, they become
ions.
– Cations are positive and are formed by elements on the
left side of the periodic chart.
– Anions are negative and are formed by elements on the
right side of the periodic chart.
Ionic compounds generally form between what?
metals and nonmetals
What is a polyatomic ion?
A group of atoms that is covalently bonded,
and yet still has a charge, is a polyatomic ion.
Writing chemical formulas:
Because compounds are electrically neutral, one
can determine the formula of a compound this
way:
– The charge on the cation becomes the subscript on the
anion.
– The charge on the anion becomes the subscript on the
cation.
– If these subscripts are not in the lowest whole-number
ratio, divide them by the greatest common factor.
Naming of binary metal-nonmetal compounds
First: name of cation(metal)
then
the name of the anion(nonmetal) with the end replaced with -ide
KI: Potassium Iodide
Polyatomic ion compounds:
Cation then anion
Binary compound between 2 nonmetals
First: nonmetal nearest to a metal
then
the ion name(-ide) of the 2nd nonmetal
use greek prefixes for both, (except mono for first nonmetal) mono, di, tri, tetra,penta,hexa,hepta,octa,nona,deca
prefixes are not used when hydrogen is one of the elements
Diatomic molecules?
Br,I,N,Cl,H,O,F
