Transcript Regents Chemistry

Regents Chemistry
Topic 2
The Periodic Table and
Formulas / Equations
Regents Chemistry
Introduction to the Table
Groups and Families
 Elements of Metals, Nonmetals and
Metalloids

Recap
•The nucleus contains
protons and neutrons
Nucleus
•Electrons surround the
nucleus in a “cloud”
•Atomic number is the
number of protons
•Atomic mass is the
sum of protons and
neutrons
electrons
The Periodic Table
The periodic table is arranged according
to Atomic Number
The first table, by Russian chemist
Dmitri Mendeleev, was arranged by
atomic mass, but this was not accurate
Current arrangement shows many
important trends..
Rows and Columns
Divisions of the Periodic Table
Metals
Alkali metals
 Alkaline earth metals
 Transition Metals

Metalloids
Nonmetals
Halogens
 Nobel gases

Periodic Table
Physical Properties of Metals
1. Efficient conduction of heat and electricity
2. Malleability (they can be hammered into
thin sheets
3. Ductility (they can be pulled into wires)
4. A lustrous (shiny) appearance
Natural States of
Elements
Most of the matter around us consists of
mixtures
Mixtures contain compounds
Atoms of individual elements are not
often found in nature in pure form
Some exceptions: gold, platinum and silver
 Also noble gases – do not combine readily


Ex; Helium gas in underground deposits
Elements after Separation..
After we use a chemical process to
separate the elements in a compound,
we find the elements to be:
Monoatomic atoms– only (1) atom of the
element
 Diatomic molecules– (2) atoms bonded
together

Examples
Argon (noble gas)
Nitrogen and
oxygen
Natural Physical States
Metals are solids at 25 C
Noble gases are gas at room 25 C and
are individual atoms
Several others are gases and diatomic
at 25 C – (H2, N2, O2, F2, Cl2)
Only two elements are liquids at 25 C

Bromine and Mercury
Elements can have different
forms…
Solid metals differ from solid non-metals
In fact, different forms of the same
element can occur

These are called allotropes
Ex: Carbon
Diamond (very hard)
 Graphite (soft)
 Buckministerfullerene (newly discovered)

End
Regents Chemistry
Information on the Table
Average Atomic Mass
 Atomic Number
 Isotopes

Regents Chemistry
Periodic Table Bingo
Regents Chemistry
Ions and Oxidation States
**Change ending of parent name to -ide and add word - ion**
Cloride Anion
***Keep parent name and add word - ion***
Sodium Cation
Ionic charges from
Periodic Table
See pg. 112
Writing out ionic charges
Gain
e-
Lose
e-
Sodium ion
Magnesium ion
Ionic Compounds
Combination of cation and anion

Write cation first and anion second
When combining, we must consider
electrical charge

Ions combine in such a way to make a zero
net charge
Total charge
of cations
+
Total charge
of anion
=
Zero net charge
Examples
More Examples...
Dissolving Ionic
CompoundsVideo
=
Does this work?
worksheet
Regents Chemistry
Chemical Nomenclature
Naming Compounds
Common names were originally
developed to name compounds

Ex: Epsom salts, milk of magnesia,
gypsum and laughing gas
Too many common names..a system
had to be developed!
Naming Compounds
Binary compounds – compounds that
are composed of two elements
We will examine two classes of binary
compounds
1. Compounds that contain a metal and a
nonmetal
 2. Compounds that contain two nonmetals

Naming Binary Ionic
Compounds
Binary ionic compounds result when a
metal combines with a nonmetal
The metal loses electrons as the
nonmetal gains electrons
The result is a positive cation (the
metal) and a negative anion (the
nonmetal)
In naming ionic compounds, we simply
name the ions
Naming Binary Ionic
Compounds
We will learn how to name two types of
ionic compounds (polyatomic ion naming
will come later)

Type I compounds – The metal is present in
only one type of cation - look at periodic table!


Ex: Na+, K+, Ca2+, Al3+
Type II compounds – The metal present can
form two (or more) cations that have different
charges - look at periodic table!

Ex: Cr2+, Cr3+, Cu+, Cu2+
Some Common
Examples
Cation Name
Anion
Name
H+
Hydrogen
F-
Fluoride
Li+
Lithium
Cl-
Chloride
K+
Potassium
Br-
Bromide
Ca2+
Calcium
I-
Iodide
Ag+
Silver
S2-
Sulfide
Naming Rules for Type I
Ionic
1. The cation is always named first and the
anion second
2. A simple cation (obtained from a single
atom) takes its name from the name of the
element.

Ex: Na+ Sodium ion
3. A simple anion (obtained from a single
atom) is named by taking the first part of the
elemental name and adding – ide

Ex: F-
Fluoride ion
Examples
Name the following compounds
CLICK TO REVEAL ANSWERS
• NaCl
sodium chloride
• KI
potassium iodide
• CaS
calcium sulfide
STOP
worksheet
Regents Chemistry
Naming Type II Compounds
Naming Type II
compounds
II compounds – The metal
present can form two (or more) cations
that have different charges - look at
periodic table!
 Type

Ex: Cr2+, Cr3+, Cu+, Cu2+
We cannot only look at the periodic table
to determine the charge…we must
determine the charge according to the
chemical formula
Determing the correct
charge
All compounds must be electrically
neutral..so
we use the charge of the anion to
determine the charge of the cation…and
multiply the charges by the number of
atoms to determine the overall net
charge
Example
CuCl
Cl comes in as Cl- : -1 x 1 Cl ion = -1
Cu must come in as a +1 :+1 x 1 Cu ion = +1
-1 + +1 = 0 , the charges balance
Copper (I) Chloride
Naming Type II Rules
Use the same system of naming as
Type I binary compounds..except
add the following after the cation
depending on the cation’s charge
(I)
(II)
(III)
(IV)
+1
+2
+3
+4
(V) +5
(VI) +6
(VII) +7
Practice
HgO
Mercury (II) Oxide
Fe2O3
Iron (III) Oxide
Worksheet
Regents Chemistry
Naming Type III Binary Compounds
Non-metal to non-metal
Type III Binary
Compounds
Type III Binary Compounds - are
compounds that contain only
nonmetals participating in covalent
bonds (sharing of electrons)
Rules for Naming Type III
1. The first element in the formula is
named first, and the full element name
is used
2. The second element is named as
though it were an anion (-ide ending)
3. Prefixes are used to denote the
numbers of atoms present.
4. The prefix mono is never used for
naming the first element
Prefixes for Naming
Type III
PREFIX
monoditritetrapentahexaheptaocta-
NUMBER INDICATED
1
2
3
4
5
6
7
8
Practice
boron trifluoride
BF3
nitrogen monoxide
NO
N2O5
dinitrogen pentoxide
carbon tetrachloride
CCl4
worksheet
Regents Chemistry
 Polyatomic
Ion Compound
Nomenclature
What’s a polyatomic
ion?
A polyatomic ion consists of two or
more elements bonded together that
posess an overall net charge that can
be used to form an ionic bond with a
metal cation
We looked at some of these!
SO42-
Polyatomic Ion Intro…
Polyatomic ions have specific
names…
You must be able to recognize
polyatomic ions in chemical
formulas and chemical names
You reference tables can help!
 See the table on the front page
Naming Polyatomic
Ions…
Some polyatomic ions have general
names that are made from modification
of the names of the elements involved
 Ex: NH4+ Ammonium Ion
CN- Cyanide Ion
Naming Oxyanions
Oxyanions are polyatomic ions (anions) that
contain atoms of an element and different
numbers of oxygen atoms
When there are two members in such a
series, the anion with the lesser number of
oxygen is given the ending –ite and the
larger number ends in –ate
Sulfite
2SO3
Ion
SO42-
Sulfate
Ion
Naming Oxyanions cont…
If there are more that two in the series,
we use the prefix hypo for the member
with the fewest oxygen and per for the
one with the most oxygen
ClO-
hypochlorite ion
ClO2-
chlorite ion
ClO3-
chlorate ion
ClO4-
perchlorate ion
Naming Compounds that
Contain Polyatomic Ions…
We use the cation name and roman
numerals (if needed) and the
polyatomic ion’s name
2 x Na+
Ex: Na2SO4
sodium sulfate
1 x SO42-
Examples
Fe(NO3)3
Mn(OH)2
CuSO4
iron (III) nitrate
manganese (II) hydroxide
copper (II) sulfate
Regents Chemistry
Revisiting the Periodic Table
 Trends of the Table
Properties of Elements
Trends to be familiar with:
Ionization Energy
 Atomic Radii
 Ionic Radii
 Electronegativity
 Reactivity of Elements

Summary of Trends
Ionization Energy – increases from left to right and
up the columns
Atomic Radii – increases from right to left and down
columns
Ionic Radii – depends on if the atom looses or gains
electrons
Electronegativity – increases from left to right and
up the columns
Reactivity – Groups 1,2 and 17 along with oxygen
are most reactive
Families on the Table
3 – day website project: see handout