Chemistry

define element

define element

A substance that cannot be broken down into simpler substances by chemical means.

define compound

a substance made up of two or more different chemical elements combined in a fixed ratio

define mixture

a physical combination of two or more substances that aren't chemically joined

What is number 1?

pure substance of compound molecules

What is number 2?

mixture of element atoms

What is number 3?

mixture of element and compound molecules

What is number 4?

mixture of compound molecules

What is number 5?

pure substance of element atoms

What is number 6?

pure substance of compound molecules

What is number 7?

pure substance of element molecules

What is number 8?

mixture of element atoms and compound molecules

What is number 9?

mixture of element molecules and atoms

What is number 10?

mixture of element and compound molecules

What is number 11?

pure substance of compound molecules

What is number 12?

mixture of compound molecules

What is number 13?

mixture of compound molecules

What is number 14?

mixture of compound molecules

What is number 15?

mixture of compound molecules

how can you classify something as an element?

It contains only one type of atom

how do you classify something as a compound?

It contains two or more different atoms joined together in a fixed ratio

how do you classify something as a mixture?

It contains two or more different substances that are only physically joined together, not chemically

Pure substances always consist of . That matter can be an or a .

one type of matter, element, compound

Is oxygen an element, compound or mixture?

element

Is carbon dioxide an element, compound or mixture?

Compound

What do the different colours of the periodic table represent?

elements with similar properties or chemical reactivity

what group does the yellow colour represent in this table?

nonmetals

what group does the blue colour represent in this table?

metals

What group does the green colour represent in this table?

metalloids

What is the purpose of the bold black line on the periodic table?

separates metals from nonmetals. Metalloids border this line

What is the zig zag line on a periodic table called?

Amphoteric line

name the first 20 elements of the periodic table

hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon, sodium, magnesium, aluminium, silicon, phosphorus, sulphur, chlorine, argon, potassium, calcium

What are rows in the periodic table called?

Periods

How are periods arranged?

represent electron shells. Each period has a specific number of shells, from 1 to 7. Elements in a period have the same number of shells, but valence electrons increase from left to right.

What are columns in the periodic table called?

Groups

How are groups arranged?

Members of the same group have the same number of electrons in the outermost shell

define metal

any of a class of substances characterized by high electrical and thermal conductivity as well as by malleability, ductility, and high reflectivity of light.

define non metal

a chemical element that lacks the characteristics of a metal

define metalloid

a chemical element that forms a simple substance having properties intermediate between those of a typical metal and a typical nonmetal.

how many metalloids are there?

6

list the metalloids

boron, silicon, germanium, arsenic, antimony and tellurium

how are metals and non metal elements different?

• Metals are solids at room temperature (except for mercury)

• metals are very hard (except for sodium) - non metals are soft (except for diamond)

• Metals are malleable and ductile - Non metals are brittle and can break down into pieces

• metals are shiny - non metals are non lustrous (except iodine)

• Metals are electropositive in nature - Non metals are electronegative in nature

• metals have high densities - non metals have low densities

elements exist as or

atoms, molecules

what is the symbol for Hydrogen?

H

what is the symbol for Helium?

He

what is the symbol for Lithium?

Li

what is the symbol for Beryllium?

Be

what is the symbol for Boron

B

what is the symbol for Carbon?

C

what is the symbol for Nitrogen?

N

what is the symbol for Oxygen?

O

what is the symbol for Fluorine?

F

what is the symbol for Neon?

Ne

what is the symbol for Sodium?

Na

what is the symbol for Magnesium?

Mg

what is the symbol for Aluminium?

Al

what is the symbol for Silicon?

Si

what is the symbol for Sulphur?

S

what is the symbol for Chlorine?

Cl

what is the symbol for Argon?

Ar

what is the symbol for Potassium?

K

what is the symbol for Calcium?

Ca

what is the symbol for iron?

Fe

what is the symbol for mercury?

Hg

what is the symbol for silver?

Ag

what is the symbol for gold?

Au

what is the symbol for copper?

Cu

what is the symbol for lead?

Pb

what is the symbol for nickel?

Ni

what is the symbol for tin?

Sn

what is the symbol for platinum?

Pt

What is Sn the chemical symbol of?

Tin

What is Pb the chemical symbol of?

Lead

What is Hg the chemical symbol of?

Mercury

What is Ag the chemical symbol of?

Silver

What is K the chemical symbol of?

Potassium

How do elements get their symbols?

It often derived from the scientific name, but can also be from the Latin name

What is the formula for water?

H₂O

What is the formula for carbon dioxide?

CO₂

What is the formula for table salt?

NaCl

Using the following formula how many atoms are there on each side?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

36

Using the following formula how many atoms of carbon are there on each side?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

6

Using the following formula how many atoms of hydrogen are there on each side?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

12

Using the following formula how many atoms of oxygen are there on each side?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

18

Is this formula balanced?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Yes

is this formula balanced?

HCl + CaCO₃ → CaCl₂ + H₂O + CO₂

If not, balance the equation

No

2HCl + CaCO₃ → CaCl₂ + H₂O + CO₂

Why is it important to balance equations

Balanced equations follow the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction, only rearranged. Balancing equations ensures that the number of atoms of each element remains the same on both sides, indicating a balanced reaction. This helps scientists determine the quantity of reactants and products in a chemical reaction.

What do compounds exist as?

Molecules

what is the difference between physical and chemical changes

Physical changes involve altering the state or appearance of a substance without changing its chemical composition. Chemical changes result in the formation of new substances with different chemical properties.

Give an example of a chemical change

An example of a chemical change is the rusting of iron, where iron reacts with oxygen in the presence of moisture to form iron oxide.

Give an example of a physical change

An example of a physical change is the melting of ice into water.

What are the indicators of a chemical change?

• Colour Change.

• Production of an odour.

• Change of Temperature.

• Evolution of a gas

• Precipitate (formation of a solid)

The formula for photosynthesis is:

6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂

What are the reactants in this formula?

Carbon dioxide, water and energy

The formula for photosynthesis is:

6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂

What are the products in this formula?

glucose and oxygen

An example of a chemical change is the rusting of iron, where iron reacts with oxygen in the presence of moisture to form iron oxide.

Write a word formula for this equation

iron + oxygen + water → iron oxide