Benchmark SC.8.P.8.5 Recognize that there are a finite number of elements and that their atoms combine in a multitude of ways to produce compounds that make up all of the living and non-living things that we encounter

Combination of elements to form compounds

CompoundsA compound is a substance which is made up of two or more elements that have been chemically combined together.

Elements chemically combined? What do you

mean?

Put the two together = sodium chloride!! Table Salt, a perfectly safe, edible compound

Sodium- is a soft silvery white metal that reacts

violently with water

CompoundsChlorine-is a poisonous, greenish yellow gas.

+

NaClSodium chloride

(table salt)

Table salt

is made

out Sodium

and

Chlorine.

Cannot be

separated by physical

means!

It is different to Sodium and different to Chlorine!

A compound… Is a substance which is made up of two or more

elements that have been chemically combined.Can be broken down into a simpler type of matter

(elements) by chemical means (but not by physical means).

Has properties that are different from its component elements. Ex: In a water molecule Hydrogen and Oxygen are gases but when they combine together they form a liquid.

Always contains the same ratio of its component atoms. Ex: In a water molecule there are 2 Hydrogen atoms per every Oxygen atom (H2O). And in a peroxide molecule there are 2 Hydrogen atoms per every 2 Oxygen atoms.

Let’s check!

What is a compound?

Cu

Is this a compound?

It only contains one type of

element.

Is this a compound?

HH

H H

OO

O

Is this a compound?

It is not chemically combined.

Why not?

Why not?

Why not?

A compound is a substance which is made up of two or more elements that have been chemically combined together.

HIt only contains

one type of element.

OHH

OHH

OHH

Yes!

Is this a compound?

Examples of compounds

ACIDS• taste sour• and turn blue

litmus paper red.

BASES feels slippery

and turns blue litmus paper darker blue.

Compounds (2+ Elements) 2 or more elements that have combined

chemically. (bonded) Can have different properties than the

elements that make them up. Example – water

Water is different than the elements hydrogen and oxygen.

Types of Substances Created from the Periodic Table

Mixtures (Heterogeneous) Combination of 2 or more substances that have NOT

combined chemically. Substances can be easily separated and still have their

own identities. Example: A supreme pizza. Every piece has a different

ratio of toppings. I can pick them of and each piece is its own entity.

Types of Substances Created from the Periodic Table

Solutions (homogeneous) Combination of 2 or more substances

that have NOT been combined chemically

The solution has the same properties throughout.

Example: Bronze is a solution. In order to be created a specific ratio of copper and tin must be mixed together. If you look at a piece of bronze, you cannot tell that there are two different elements present.

Types of Substances Created from the Periodic Table

ACIDS Produce H+ (as H3O+) ions in water Tastes sour. REACTS with metals React with bases to form salts and

water BASES

Produce OH- ions in water Taste bitter, chalky Feel soapy, slippery React with acids to form salts

and water

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Atoms! The Legos of the

Universe

The Atom

Atom: the smallest unit of matter, a nucleus surrounded by an electron cloud.

“atom” is from the Greek word “atomos” which means “not able to be divided.”

Inside the atom

All atoms are made of the same 3 subatomic (smaller than an atom) particles.

Inside the atom…

Inside the nucleus of an atom

Inside the nucleus of an atom

Key Questions

If there are both protons and neutrons in the nucleus, why does the nucleus have a positive charge?

Protons are positive, and neutrons are neutral, so they don’t give any charge!

Outside the nucleus…

The Atom

Electron

Nucleus

Neutron

Electron Cloud

Proton

+

-

0

How Do You Weigh an Atom?

What units do you use to measure the mass of an atom? Atomic Mass Units (AMU)

Atomic Mass Units (AMU) 1 AMU = Mass of one proton 1 AMU = Mass of one neutron

Sizes of Subatomic Particles

How big are protons, electrons, and neutrons compared to each other?

+ 0 -

BigTiny

Summary of Key Concepts

Particle Charge Mass (AMU)

Location

Proton + 1 Nucleus

Electron - 1/1830 ≈ 0

Electron Cloud

Neutron Ѳ 1 Nucleus

Summary of Key Concepts

Protons (+) = Electrons (-)

#Neutrons = Atomic Mass – Atomic

Number

Atomic Mass = # Protons + # Neutrons

Formative Checkpoint(Fill in this table)

Does it Have CELLS?

Does it have ATOMS?

Living Things

Non-Living Things

Elements

The elements, alone or in combinations, make up our bodies, our world, our sun, and in fact, the entire universe.

Key to the Periodic Table

Elements are organized on the table according to their atomic number, usually found near the top of the square. The atomic number

refers to how many protons an atom of that element has.

For instance, hydrogen has 1 proton, so it’s atomic number is 1.

The atomic number is unique to that element. No two elements have the same atomic number.

What’s in a square?

Different periodic tables can include various bits of information, but usually: atomic number symbol atomic mass number of valence

electrons state of matter at

room temperature.

Atomic Number

This refers to how many protons an atom of that element has.

No two elements have the same number of protons.

Bohr Model of Hydrogen Atom

Wave Model

Atomic Mass Atomic Mass

refers to the “mass” of the atom.

It is derived at by adding the number of protons with the number of neutrons.

HThis is a helium atom. Its atomic mass is 4 (protons plus neutrons).

What is its atomic number?

ADD a Proton from left to right

Families Periods

Columns of elements are called groups or families.

Elements in each family have similar but not identical properties.

For example, lithium (Li), sodium (Na), potassium (K), and other members of family IA are all soft, white, shiny metals.

All elements in a family have the same number of valence electrons.

Each horizontal row of elements is called a period.

The elements in a period are not alike in properties.

In fact, the properties change greatly across even given row.

The first element in a period is always an extremely active solid. The last element in a period, is always an inactive gas.

Hydrogen

The hydrogen square sits atop Family AI, but it is not a member of that family. Hydrogen is in a class of its own.

It’s a gas at room temperature. It has one proton and one electron

in its one and only energy level. Hydrogen only needs 2 electrons to

fill up its valence shell.

Alkali Metals The alkali family is found

in the first column of the periodic table.

Atoms of the alkali metals have a single electron in their outermost level, in other words, 1 valence electron.

They are shiny, have the consistency of clay, and are easily cut with a knife.

Alkali Metals They are the most

reactive metals. They react

violently with water.

Alkali metals are never found as free elements in nature. They are always bonded with another element.

Matter

All matter is composed of atoms and groups of atoms bonded together, called molecules. Substances that are made from one type

of atom only are called pure substances. Substances that are made from more

than one type of atom bonded together are called compounds.

Compounds that are combined physically, but not chemically, are called mixtures.

Elements, Compounds, Mixtures

Sodium is an element.

Chlorine is an element.

When sodium and chlorine bond they make the compound sodium chloride, commonly known as table salt.

Compounds have different properties than the elements that make them up.

Table salt has different properties than sodium, an explosive metal, and chlorine, a poisonous gas.

Elements, Compounds, Mixtures

Hydrogen is an element. Oxygen is an element. When hydrogen and

oxygen bond they make the compound water.

When salt and water are combined, a mixture is created. Compounds in mixtures retain their individual properties.

The ocean is a mixture.

Elements, compounds, and mixtures

Mixtures can be separated by physical means.

Compounds can only be separated by chemical means.

Elements are pure substances. When the subatomic particles of an element are separated from its atom, it no longer retains the properties of that element.