regents chemistry topic 2 the periodic table and formulas / equations

Regents Chemistry

Topic 2

The Periodic Table and Formulas / Equations

Regents Chemistry

Introduction to the TableGroups and FamiliesElements of Metals, Nonmetals and

Metalloids

Recap

Nucleus

electrons

•The nucleus contains protons and neutrons

•Electrons surround the nucleus in a “cloud”

•Atomic number is the number of protons

•Atomic mass is the sum of protons and neutrons

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

MetalsAlkali metalsAlkaline earth metalsTransition Metals

Metalloids

NonmetalsHalogensNobel 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 ElementsMost 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 silverAlso 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

elementDiatomic 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 CBromine and Mercury

Elements can have different forms…

Solid metals differ from solid non-metalsIn fact, different forms of the same element can occurThese are called allotropes

Ex: CarbonDiamond (very hard)Graphite (soft)Buckministerfullerene (newly discovered)

End

Regents Chemistry

Information on the TableAverage Atomic MassAtomic 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

Sodium ion

Magnesium ion

Gain e-

Losee-

Ionic Compounds

Combination of cation and anionWrite cation first and anion second

When combining, we must consider electrical charge Ions combine in such a way to make a zero

net chargeTotal chargeof cations

+ Total chargeof anion

= Zero net charge

Examples

More Examples...

=

worksheet

Dissolving Ionic CompoundsVideo

Does this work?

Regents Chemistry

Chemical Nomenclature

Naming Compounds

Common names were originally developed to name compoundsEx: 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 compounds1. 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 nonmetalThe metal loses electrons as the nonmetal gains electronsThe result is a positive cation (the metal) and a negative anion (the nonmetal)In naming ionic compounds, we simply name the ions

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+

Naming Binary Ionic Compounds

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

ExamplesName the following compounds

• NaCl

• KI

• CaS

sodium chloride

potassium iodide

calcium sulfide STOPworksheet

CLICK TO REVEAL ANSWERS

Regents Chemistry

Naming Type II Compounds

Naming Type II compounds

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+

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) +1 (V) +5(II) +2 (VI) +6(III) +3 (VII) +7(IV) +4

Practice

HgO

Fe2O3

Mercury (II) Oxide

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 III1. 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 NUMBER INDICATED

mono- 1di- 2tri- 3tetra- 4penta- 5hexa- 6hepta- 7octa- 8

Practice

BF3

NO

N2O5

carbon tetrachloride

boron trifluoride

nitrogen monoxide

dinitrogen pentoxide

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 namesYou 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 involvedEx: 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

SO32- SO4

2-Sulfite Ion

Sulfate Ion

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

Naming Oxyanions cont…

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

Ex: Na2SO4

Na+

SO42-

2 x

1 xsodium sulfate

Examples

Fe(NO3)3 iron (III) nitrate

Mn(OH)2manganese (II) hydroxide

CuSO4copper (II) sulfate

Regents Chemistry

Revisiting the Periodic TableTrends of the Table

Properties of Elements

Trends to be familiar with: Ionization EnergyAtomic Radii Ionic RadiiElectronegativityReactivity 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