THE CHEMICAL

ELEMENTS 3º

ESO

SERGIO SALOBREÑA

LUCENA

FUENGIROLA

ELEMENTS CLASIFICATION

THE CLASSIFICATION OF THE ELEMENTS IN METALS AND NON-

METALS IS THE SIMPLEST, AS IT APPLIES AS A CLASSIFICATION

CRITERIA ITS APPEARANCE AND SOME PHYSICAL PROPERTIES.

• METALS: THEY ARE OPAQUE AND HAVE METALLIC BRIGHTNESS.

DRIVE HEAT AND ELECTRICITY WELL. THEY ARE MALLEABLE (IT CAN

BE DECOMPOSED IN THIN SHEETS) AND DUCTILE (IT CAN BE

STRETCHED BY FORMING WIRES). ELEVATED POINTS OF FUSION

AND EBULLITION. EXAMPLES: IRON, COPPER, ZINC, TIN, GOLD ...

• NON-METALS: DO NOT HAVE METAL SHINE. BAD CONDUCTORS OF

HEAT AND ELECTRICITY. THEY ARE NOT MALEABLE OR DUCTILE.

VERY LOW FUSION AND EBULLITION POINTS. EXAMPLES:

HYDROGEN, OXYGEN, CHLORINE, BROMINE, SULFUR, FLUORINE,

NEON, CARBON, ETC.

EXERCISES

1. WHAT IS THE SIMPLEST CLASIFICATION OF ELEMENTS?

2. WHAT DOES DUCTILE MEAN? AND MALLEABLE?.

3. WRITE THREE PROPERTIES OF METALS.

4. WRITE THREE PROPERTIES OF NON-METALS.

5. WHICH OF THE FOLLOWING DATA BELONGS TO GOLD? AND THE PHOSPHORUS?

A) POINT OF FUSION= 1064 ºc B) POINT OF FUSION= 44,2 ºC

C) IT CAN´T BE DECOMPOSED IN THIN SHEETS. D) POINT OF EBULLITION= 280ºC

E) IT CAN BE STRECHED BY FORMING WIRES. F) POINT OF EBULLITION= 2856ºC

G) IT IS A BAD CONDUCTOR OF HEAT. H) IT HAS METALLIC BRIGHTNESS

FIRST PERIODIC CLASIFICATIONS

IN 1869, D. MENDELEIEV DISPOSE OF THE 63 CHEMICAL ELEMENTS

KNOWN IN THAT TIME IN GROWTH ORDER ACCORDING TO THEIR

ATOMIC MASSES, AND FOUND THAT THOSE WHO HAD SIMILAR

PROPERTIES WERE LOCATED IN THE SAME HORIZONTAL ROW.

THE ATOMIC MASS

THE ATOMIC MASS OF AN ELEMENT IS THE MASS OF AN ATOM OF

THAT ELEMENT. HOWEVER, IT DOES NOT BE EXPRESSED A LOT OF

THIS MEASURE TO BE VERY SMALL. FOR EXAMPLE: THE MASS OF A

HYDROGEN ATOM IS AROUND 10-27 Kg.

USUALLY IS USED THE RELATIVE ATOMIC MASS THAT IS THE MASS

OF AN ATOM COMPARED TO THE MASS OF THE TWELVE PART OF

THE ATOM OF C12. IT IS AN ADIMENSIONAL UNIT DENOMINATED

ATOMIC MASS UNIT THAT IS THE TWELVE PART OF THE MASS OF AN

ATOM OF C12 (u.m.a.).

THE ATOMIC RELATIVE MASS OF AN ELEMENT DOES NOT BE A

WHOLE NUMBER, BECAUSE MOST ELEMENTS HAVE SEVERAL

ISOTOPES IN NATURE IN DIFFERENT PERCENTAGES.

LA MASA ATÓMICA

LA MASA ATÓMICA RELATIVA

EXERCISES

1. WHO PERFORMED THE FIRST PERIODIC TABLE OF THE ELEMENTS? WHAT

CRITERIA DID HE USE TO CLASSIFY THEM?

2. WHAT IS THE ATOMIC MASS OF AN ELEMENT? AND THE RELATIVE ATOMIC

MASS OF AN ELEMENT? .

3. WHAT DOES U.M.A. MEAN? WHATT IT IS?.

4. CALCULATES THE ATOMIC RELATIVE MASS OF THE LITHIUM KNOWING

THAT IN NATURAL CONDITION THIS ELEMENT CONTAINS A 7.42% ISOTOPE

OF RELATIVE ATOMIC MASS 6, AND A 92.58% OF RELATIVE ATOMIC MASS

ISOTOPE 7.

CURRENT CLASSIFICATION OF THE

ELEMENTS

THE CURRENT PERIODIC TABLE ORGANIZES 118 ELEMENTS, OF WHICH 30

HAVE BEEN OBTAINED ARTIFICIALLY IN THE LAST DECADES.

THESE ELEMENTS ARE PLACED IN GROWING ORDER ACCORDING TO THEIR

ATOMIC NUMBER GROUPED BY GROUPS AND PERIODS.

• GROUP: IS EACH OF THE VERTICAL COLUMNS OF THE PERIODIC TABLE. THE

ELEMENTS OF THE SAME GROUP HAVE THE SAME NUMBER OF VALENCE

ELECTRONS, THEREFORE THEY SHARE SIMILAR CHEMICAL PROPERTIES.

• PERIOD: EACH OF THE HORIZONTAL ROWS OF THE PERIODIC TABLE. THE

ELEMENTS OF THE SAME PERIOD HAVE THE SAME NUMBER OF ELECTRONIC

LEVELS.

THE ELEMENTS WITH ATOMIC NUMBER FROM 58 TO 71 (LANTANIDOS) AND

FROM 90 TO 103 (ACTÍNIDOS) ARE SITUATED IN TWO ROWS OUTSIDE THE

TABLE.

METALS AND NON-METALS IN THE PERIODIC TABLE

WITHIN THE SAME PERIOD METALLIC PROPERTIES INCREASE AS WE MOVE

TO THE LEFT.

WITHIN THE SAME GROUP, METALLIC PROPERTIES INCREASE AS WE GO

DOWN ON THE TABLE.

EXERCISES

1. HOW MANY ELEMENTS ARE IN THE CURRENT PERIODIC TABLE?

2. DEFINE PERIOD AND GROUP.

3. WHAT DOES THE CURRENT CLASSIFICATION OF THE ELEMENTS OF

MENDELEIEV CLASSIFICATION DIFFER FROM?

4. TRUE OR FALSE:

A) CHLORINE HAS MORE METAL CHARACTER THAN SODIUM.

B) THE IODINE HAS MORE METAL CHARACTER THAN FLUOR.

C) SODIUM HAS MORE METAL CHARACTER THAN MAGNESIUM.

D) CALCIUM HAS MORE METAL CHARACTER THAN MAGNESIUM.

GROUP 1: THE ALKALINE ELEMENTS

THE ALKALINE ELEMENTS ARE METALS, EXCEPT THE HYDROGEN. THEIR

ELECTRONIC CONFIGURATION WILL ALWAYS PRESENT A SINGLE ELECTRON

IN ITS LAST LAYER, SO THAT THEY WILL HAVE VALENCE +1. TO ACHIEVE

GREATER STABILITY, THEY TEND TO LOSE THIS ELECTRON GIVING PLACE TO

CATIONS (IONS WITH POSITIVE CHARGE). THE ALKALINE ELEMENTS ARE: H,

Li, Na, K, Rb, Cs and Fr.

GRUPO 2: THE ALKALINE EARTH ELEMENTS

THE ALKALINE EARTH ELEMENTS ARE LESS REACTIVE METALS THAN THE

ALKALINE METALS. THEY ARE CHARACTERIZED BECAUSE THEY PRESENT 2

ELECTRONS IN THEIR LAST LAYER, SO THEY WILL HAVE VALENCE +2. TO

ACHIEVE GREATER STABILITY EASILY LOSE THESE TWO ELECTRONS, GIVING

PLACE TO CATIONS WITH CHARGE +2. ALKALINE EARTH ELEMENTS ARE: Be,

Mg, Ca, Sr, Ba AND Ra.

GROUP 18: THE NOBLE GASES

THE NOBLE GASES. THEY ARE NOT METALS THAT HAVE A LITTLE TENDENCY

TO COMBINE WITH OTHER ELEMENTS, DUE TO THEIR LAST LAYER IS

COMPLETED AND THEY ARE VERY STABLE. FOR THIS REASON THEY ARE IN

THE FORM OF ISOLATED ATOMS IN NATURE, THING THAT DOES NOT HAPPEN

WITH THE ALKALINES OR ALKALINE EARTH ELEMENTS. NOBLE GASES ARE:

He, Ne, Ar, Kr, Xe, Rn.

GROUP 17: THE HALOGEN ELEMENTS

THE HALOGEN ARE NON-METALS THAT TEND TO CONNECT WITH OTHER

ELEMENTS (THEY ARE VERY REACTIVE). THIS IS DUE TO ELECTRONIC

CONFIGURATION LACK AN ELECTRON TO COMPLETE THEIR LAST

LAYER. THEY HAVE TRENDS TO WIN AN ELECTRON, GIVING PLACE TO

NEGATIVE IONS (ANIONS) AND THEIR VALENCE IS

-1. HALOGEN ELEMENTS ARE: F, Cl, Br, I, At.

REPRESENTATIVE AND TRANSITIONAL ELEMENTS

THE REPRESENTATIVE ELEMENTS ARE THOSE THAT BELONG TO GROUPS 1,2

AND FROM 13 TO 18. ARE CHARACTERIZED BECAUSE IN NEUTRAL STATE

ONLY PRESENT ELECTRONIC LAYERS S AND P.

THE ELEMENTS OF TRANSITION ARE THOSE LOCATED IN THE CENTRAL PART

OF THE PERIODIC TABLE (GROUPS FROM 3 TO 12), WHOSE MAIN

CHARACTERISTIC IS THE PRESENCE IN ITS NEUTRAL STATE OF ORBITAL D.

EXERCISES

1. WHAT CHARACTERIZES THE ALKALINE ELEMENTS?

2. WRITE THE ALKALINE EARTH ELEMENTS. WHAT IS THEIR VALENCE?

3. WHY NOBLE GASES DO NOT FORM IONS IN NATURE?

4. WHY THE HALOGEN ELEMENTS TEND TO FORM NEGATIVE IONS?

5. DEFINE REPRESENTATIVE AND TRANSITIONAL ELEMENTS.

THE CHEMICAL LINK

WE CAN DEFINE CHEMICAL LINK AS AN ATTRACTION OF ELECTROSTATIC

TYPE BETWEEN TWO OR MORE ATOMS THAT ALLOWS THEM TO ACHIEVE

STABILITY.

THE HYDROGEN ATOM HAS ONLY 1 ELECTRON IN ITS LAST LAYER, BUT IF

TWO ATOMS OF HYDROGEN ARE APPROXIMATE THE SUFFICIENT CAN LINK

ITS ELECTRONIC LAYERS AND SHARE THEIR 2 e-. SO, BOTH REACH THE

STABILITY THAT PROVIDES HAVING THE LAST FULL LAYER.

TYPES OF CHEMICAL LINKS

IF IT HAPPENS IN THE HYDROGEN ATOM, THE LINK IS PRODUCED BY SHARING

ELECTRONS IS A COVALENT LINK. EXAMPLES OF THIS TYPE OF LINKS ARE

THE DIATOMIC MOLECULES AS OXYGEN (O2), NITROGEN (N2), CHLORINE (Cl2),

BROMINE (Br2) OR FLUOR (F2). THE COVALENT LINK IS REPRESENTED WITH

THE F-F SYMBOL (-).

FORMATION OF COVALENT CRYSTALS

THE CARBON ATOM HAS 4 e- IN ITS LAST LAYER. TO COMPLETE THE LAST

LAYER AND ACHIEVE STABILITY, IT NEEDS TO SHARE THEM WITH OTHER 4

ATOMS OF CARBON, THAT IS, FORMING 4 COVALENT LINKS. IN THIS

PROCESS, IT GIVES PLACE TO A CRYSTAL, A SOLID WHOSE PARTICLES ARE

ORDERED ACCORDING TO A PATTERN THAT IS REPEATED CONSTANTLY. THE

CARBON, ACCORDING TO THE SPACE PATTERN THAT FOLLOWS, CAN BE

FOUND IN NATURE IN TWO VARIETIES:

• DIAMOND: EACH ATOM OF CARBON IS LINKED TO OTHER FOUR CARBON

ATOMS ON A SAME PLANE. AS THERE ARE NO FREE ELECTRONS, IT DOES

NOT DRIVE THE ELECTRICAL CURRENT. IT IS A VERY STABLE NETWORK THAT

MAKES IT A VERY HARD SOLID, WITH HIGH POINTS OF FUSION AND

EBULLITION.

• GRAPHITE: EACH ATOM OF CARBON IS LINKED TO OTHER THREE ATOMS OF

CARBON ON A SAME PLANE, AND IN ADJACENT PLANS TO A FOURTH. THIS

LAST UNION IS MORE WEAK, SO THAT GRAPHITE LEADS THE ELECTRICITY

AND IS SOFT TO THE TOUCH.

EJERCICIOS

PÁGINA 53 EJERCICIO 7.

PÁGINA 54 EJERCICIOS 8,9,10.

TYPES OF CHEMICAL LINKS

MOST OF THE METALS HAVE 1,2 OR 3 e- IN THEIR LAST LAYER. IN A METALLIC

CRYSTAL, THE ATOMS THAT COMPOSE IT ARE POSITIVE IONS THAT HAVE

LOST THOSE EXTERNAL ELECTRONS, WHICH DO NOT BELONG TO A

CONCRETE ATOM (THEY ARE SAYED TO BE DELOCALIZED), MOVING

BETWEEN THE IONS OF THE CRYSTAL NETWORK.

WHEN THE ELECTRONS CAN BE MOVED WITH GREAT FREEDOM, METALS ARE

GOOD CONDUCTORS OF ELECTRICITY.

SO WE CAN DEFINE THE METALLIC LINK LIKE THAT ESTABLISHED BETWEEN A

GREAT NUMBER OF CATIONS THAT ARE KEPT UNITED BY A CLOUD OF

ELECTRONS.

EJERCICIOS

PÁGINA 53 EJERCICIO 7.

PÁGINA 54 EJERCICIOS 8,9,10.

EXERCISES

1. DEFINE: CHEMICAL LINK, COVALENT LINK AND METALLIC LINK.

2. HOW MANY ATOMS OF CARBON ARE UNITED TO EACH ATOM OF CARBON IN

THE DIAMOND AND HOW MANY ARE IN THE GRAPHITE?

3. HOW MANY ATOMS OF CARBON ARE UNITED ON THE SAME PLANE FOR

EVERY CARBON ATOM OF THE DIAMOND AND HOW MANY ARE AT THE SAME

PLANE IN THE GRAPHITE?

4. THE TERM A SEA OF ELECTRONS WOULD YOU RELATE TO WHAT TYPE OF

LINK?