Lab #2 Periodic Table – Part 1 Chemistry 108 Instructor: Robert Goldman

Lab #2Periodic Table – Part 1

Chemistry 108

Instructor:Robert Goldman

The Periodic Table

Elements

Hydrogen, Helium, Lithium, etc…– Each has its own specific symbol– First letter is capitalized, second is lowercase.

Ex: He for Helium, Li for Lithium What is the difference between Co and CO?

Elements are composed of only one type of atom! Ex: Cl2

MEMORIZE THE NAMES AND SYMBOLS FOR AT LEAST THE FIRST 32 ELEMENTS ON THE PERIODIC TABLE!

Compounds

Compounds contain more than one type of element (or atom).

CO contains Carbon AND oxygen, and is therefore a compound.

Compounds can be broken down into their elemental parts.

Subscripts and Coeffecients

2CH3OHCoeffecient Subscript

A coeffecient applies to the whole molecule is preceeds. A subscript applies ONLY to the atom (or atoms in parenthesis) it follows.

More on Subscripts and Coeffecients

4CH3(CH2)2CH3

•The coeffecient means there are 4 molecules of CH3(CH2)2CH3 present.

•CH3(CH2)2CH3 the “2” following the part in red indicates there are two CH2s present.

•How many of each element are present in the above?

More on Subscripts and Coeffecients

4CH3(CH2)2CH3

In each of the 4 molecules present, there are:

4 carbons: 4CH3(CH2)2CH3

10 hydrogens: 4CH3(CH2)2CH3

Multiply by the coeffecient of 4:

4x4=16 carbons and 10x4=40 hydrogens

Metals

Shiny in appearance. Generally good conductors of heat and

electricity. Solid at room temperature, with one exception. Monatomic (one atom)

– Ex. Al (aluminum)

Non-Metals

Not shiny in appearance. Generally not good conductors or heat or

electricity. Mostly brittle solids or gasses at room

temperature. Some are diatomic (two atoms)

– Ex. Cl2 (chlorine)

Noble Gasses

All gasses at room temperature. Located on the far right of the periodic table. Known for their stability (relatively non-

reactive).

Transition Elements

A group of elements with intermediary properties located between metals and non-metals.

These share characteristics of both groups.

Information on the Periodic Table

Atomic Subunits

•Protons (positive charge), weigh 1 amu

•Neutrons (neutral charge), weigh 1 amu

•Electrons (negative charge), 1/1800 amu

Components of an Element

The “4” is the atomic mass number and the “2” is the atomic number.

The atomic mass the the number of protons plus the number of neutrons.

He4

2

Components of an Isotope

Isotopes elements that vary only in their number of neutrons.

How many protons and neutrons are in each of the above?

Which of the above is HEAVIER?

C14

6C12

6

Ions

Formed when an element gains or loses electrons.

F + e- F-

S + 3e- S-3

Or

K K+ + e-

Ca Ca2+ + 2e-

The above are all monatomic ions.

Polyatomic Ions

Formed when a compound gains or loses electrons.

Which of these (in red) is an ion?Na+ + Cl- NaCl

or

N + O3- NO3

-

Rutherford’s Gold Foil Experiment

Rutherford’s Gold Foil Experiment

Discharge Tube

Today in lab…

Part 1

Complete Table A from items on the reagent table.

Symbol

Physical State

Color

Metallic Luster

Today in Lab

Part 2 - Pyrolysis

Obtain two test tubes, fill one 1/3 with table sugar and the other 1/3 with zinc.

Carefully heat over a Bunsen burner (using tongs) and record observations in Table B.

What would you expect for an element vs. a compound?

Today in Lab

Part 3

Examine the ball-and-stick models. Using the explanation of atom colors in your lab manual, fill in Table C with chemical formulas, etc.

Today in Lab

Part 4

Look at the discharge tube setup and manipulate the electron stream with a magnet WITHOUT TOUCHING THE APPARATUS.

Diagram the apparatus and make observations in the space provided in your lab handout.

Today in Lab

Part 5

Complete Table D by filling in the missing information for each atom given.

Don’t forget…

Hand in your lab and lab exercises before leaving today.

Have homework #2 ready to hand in at the beginning of class next week.