Chapter 5 Science Study Guide

Mrs. Etsell CHAPTER 5K SCIENCE STUDY GUIDE

T H E P E R I O D I C T A B L E

“Periodic” means repeated in a pattern.

Periodic Table – the arrangement of the elements according to repeated changes in properties. It was designed by Dimitri Mendeleev.

Dimitri Mendeleev first arranged the elements in the periodic table according to how they act and by increasing atomic mass

.

British scientist, Henry Mosely, corrected Mendeleev’s arrangement by ordering the elements according to increasing atomic number.

Periodic Law – states that the chemical and physical properties of elements are periodic functions of their atomic numbers.

Groups are the vertical columns

Periods are the horizontal rows

Group 1 contains H, Li, Na, Rb, Cs,. Fr, Pb – all these elements act alike BECAUSE they all have the same number of electrons (1) in their outer level

H Li Na K

Their are 18 groups in the Periodic Table. Each group’s elements have the same number of electrons in their outer level.

So…….All elements in group 1, have 1 electron in their outer level

All elements in group 2, have 2 electrons in their outer level

All elements in group 3, have 3 electrons in their outer level

Elements are CLASSIFIED as either metals, nonmetals, or metalloids.

METALS:

·  Are malleable (can be flattened by hammering)

·  Are good conductors of thermal energy

·  Are ductile (can be drawn through thin wires)

·  Tend to be shiny

·  Most have few electrons in their outer level

·  Most are solids at room temperature

·  Mercury, however, is a metal that is a liquid at room temperature

NONMETALS

·  Found to the right of the zigzag line

·  Their outer levels are almost full

·  Nonmetals called Nobel Gases have a completely filled outer level of electrons.

·  Nonmetals are not malleable or ductile and are poor conductors of thermal energy.

METALLOIDS

·  Also called semiconductors

·  They are found on/around the zigzag line

·  Most have a half-filled outer level of electrons

·  Some metalloids are like metals and some are like nonmetals

CHEMICAL SYMBOLS

·  Each element has a chemical symbol

·  Names of elements often come from the scientist that discovered them.

·  Others are names according to the places they were studied or found in

Example: Sulfur (name) S (symbol)

Calcium (name) Ca (symbol)

PERIODS

·  The horizontal rows of elements on the periodic table

·  The elements in a row become less metallic from left to right

·  Elements at the left are very metallic

·  Elements further right are less metallic

·  Elements at the far right on a row are nonmetals

GROUPS

·  The vertical columns of elements on the periodic table

·  Elements in the same group have similar chemical and physical properties

·  Groups are also called families

GROUP NUMBER – tells how many electrons are on the outer level

PERIOD NUMBER – tells which level is the outer level

Example: Potassium (K) is in group 1, period 4.

That means it has 1 electron on its outer level, based on its group

number and its outer level is level 4, based on its period number.

Calcium is in group 2, period 4

That means it has 2 outer level electrons on level 4.

GROUPING ELEMENTS

·  The most reactive elements are in groups 1 and 2

·  These elements have 1 or 2 electrons in their outer levels

·  They only have to give up 1 or 2 electrons to have a filled outer lever and therefore, are very reactive

GROUP 1 – Alkali Metals

·  Have 1 electron in their outer level

·  Are very reactive

·  Are soft enough to be cut with a knife, silver-colored, shiny, have a low density

GROUP 2 – Alkaline-earth Metals

·  Have 2 electrons in their outer level

·  Are very reactive, but less reactive than the alkali metals in group 1

·  This is because it is more difficult to give up 2 electrons that 1 electron

GROUPS 3-12: TRANSITION METALS

·  Contains metals

·  Have 1 or 2 electrons in their outer levels

·  Are less reactive than the alkaline-earth metals in group 2

·  Transition elements do not give away electrons as easily as those in groups 1 and 2

·  Titanium is a transition element used to make artificial hips and is not very reactive

·  Iron is also a transition element, but is very reactive

GROUPS 13-16 - GROUPS WITH METALLOIDS

·  Group 13 - the Boron Group – has 3 outer level electrons

·  Group 14 - the carbon Group has 4 outer level electrons (diamonds are a natural form of an element in the carbon group)

·  Group 15 - the Nitrogen Group has 5 outer level electrons

·  Group 16 - the Oxygen Group has 6 outer level electrons

GROUPS 17 AND 18: Nonmetals Only

·  GROUP 17 - the Halogens.

·  They have 7electrons in their outer level

·  are the most reactive nonmetals (only need 1 electron for a full level)

·  They are poor conductors of electricity

·  Fluorine, Chlorine, Bromine, Iodine and Astatine are group 17 halogens.

·  Note* When group 1 elements combine with gropu 17 – they form a salt compound – EX. Lithium bromide, Sodium fluoride, Potassium chloride. Etc.)

GROUP 18 – THE NOBEL GASES

·  These are unreactive nonmetals

·  Their outer energy levels are full and they don’t need to gain or lose electrons

·  Helium, Neon, Argon, Krypton, Xenon, and Ununoctium are Nobel Gases

·  Argon is the most abundant noble gas in our atmosphere.

USES OF NOBEL GASES:

·  Light bulbs filled with argon last longer

·  Neon used in “neon lights” produce an orange-red color

HYDROGEN

·  Its properties are unlike the properties of any other group of elements.

·  It has 1 electron on its outer level

·  It is reactive

·  It is a colorless, odorless gas at room temperature

·  Reacts explosively with oxygen

·  It is used as a fuel in rockets

·  Its properties are more like nonmetals than metals

·  Hydrogen is the most abundant element in the universe

LANTHANIDES

·  Transition metals from

·  Period 6 that are placed at the bottom of the periodic table.

·  They are shiny and reactive

·  Some of these elements are used to make steel

ACTINIDES

·  Transition elements from Period 7 that are placed at the bottom of the periodic table.

·  All actinide atoms are unstable and radioactive

·  Americium, element 95, is used in smoke detectors

Both Lanthanides and Actinides are placed at the bottom of the periodic table to keep the table from being too wide

AIR

Breath in Breath out

Nitrogen 80% Nitrogen 80%

Oxygen 18% Oxygen 13%

Argon 1% Carbon Dioxide 5%

Mix 1% Argon 1%

Mix 1%