Unit 5 elements

Natural Occurrence and Bonding

The Elements at Play

Vocabulary Nouns

Occurrence

Abundance

Earth’s crust

Sodium

Living things

Grouping

Verbs

To house

To constitute

To carry out

To make up

To be made up (of)

To tend

Adjectives

Vital

Common

Variable

Abundant

Abundance of Elements in Nature

Of the 118 elements that appear in the Period Table,

the Earth houses 90. The elements that come after

Uranium (atomic number 92) are not found in

nature, and have been obtained artificially.

Hydrogen (H) and Helium (He)

Hydrogen and Helium are the most abundant elements in the

Universe.

Because H and He are small, they formed very quickly in the

first few seconds after the Big Bang. According to the Big

Bang theory, four minutes after the start of our Universe, its

chemical composition by mass was 76% H and 24% He.

Non-metals: Abundant in living

organisms and the atmosphere

Living things on Earth are mostly composed of elements from

groups 14 to 17 of the Periodic Table, according to the following

proportions:

Primary Bioelements: Constitute 96% of living matter: C, H, O,

N, S and P. (Carbon, Hydrogen, Oxygen, Nitrogen, Sulfur, and

Phosphorous).

Secondary Bioelements: They are important for carrying out

vital functions, and make up 3.3%: Ca, Na, K, Mg, Cl

Oligoelements : Appear in living matter in amounts less than

0.1%: Some include: Fe, Mn, Zn, F, I B, Si, V, Co, Se, Mo, Sn.

Metals: the most numerous, in small

quantities

Of all of the elements of the Periodic Table, approximately

four fifths (4/5) are metals!

However, they are also the least abundant in Nature.

In fact, even in the Earth’s Crust, O and Si make up about

73% and they are non-metals. Then there’s: Al (aluminum),

Fe (iron), Ca (calcium), Na (sodium), K (potassium) and

Mg (magnesium); and, in much smaller proportion, the rest.

Sodium-Potassium Pump

An example of a vital bodily function that requires

Potassium (K) is the sodium-potassium pump that

regulates the concentration of chemicals within the

cells of living organisms, including humans!

Semi-metals:

components of the electronic age

The elements situated on the border between metals and

non-metals have their own characteristics. Elements such as

Si (silicon), Ge (germanic), or As (arsenic) are called semi-

conductors and are the basic components of current

electronics.

Review: How many elements are there?

How are they organized in the Periodic Table?

a. By their radioactivity

b. By the number of protons they have

c. By the number of neutrons they have

d. By the number of isotopes they have

Which elements in the periodic table are non-metals?

Which elements in the periodic table are metals?

interactive

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Vocabulary II Nouns

Electronegativity

Gout (drop)

Octet rule

Cation

Anion

Lattice

Joint

Accordance

Wire

Hint

Adjectives

Electronegative

Ambient (as in ambient temperature)

Phrases

In order to

Verbs

To share

To gain

To accept

To lose

To get rid of (to escape)

Molecules and Crystals:

Two Types of Atomic Groupings

Molecules

Molecules are generally small substances, and formed by a

definite or certain number of atoms. They can be:

Elemental Molecules: formed from one element

Ex.: O3, which makes up the ozone layer

that protects us from UV radiation.

Compound Molecules: formed from different atoms.

Ex.: Carbon dioxide (CO2), or Sulfur trioxide (SO3).

Crystals

Crystal nets are generally big substances, and are formed

by a variable number of atoms, ions, or molecules that tend

to form a regular three dimensional structure.

Just like molecules, crystals can be:

Elemental crystals: formed by identical atoms.

Ex: Nickel (Ni), diamond (C)

Compound crystals: formed by different atoms.

Ex: Sodium chloride (NaCl) = Table Salt

Cl-

Na+

Molecules vs. Crystals

Usually very small

Made up of a definite

number of atoms.

Can be elemental or

compound.

Usually very big

Made up of a variable

number of atoms, ions

or molecules.

Can be elemental or

compound.

Are there crystals in our bodies?

Crystals can sometimes be formed in the human body.

For example, urea crystals

found in a urine sample

indicate high levels of uric acid in

the blood. This situation presents as

the disease gout (la gota), in which

crystals form in joints.

Uric acid crystals from a

fluid sample photographed

under a microscope.

Molecule or Crystal?

1. “A stable grouping of atoms is formed by thousands of

identical atoms organized in space.”

Will it be a molecule or crystal?

Elemental type or compound type?

2. “A stable grouping of atoms is formed by 3 atoms: 2 of

oxygen and 1 of sulfur.”

Are we talking about a molecule or crystal?

Elemental type or a compound type?





































Education

Unit 5 elements