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.
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What are columns in the periodic table called?
Groups
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How are groups arranged?
Members of the same group have the same number of electrons in the outermost shell
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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.
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define non metal
a chemical element that lacks the characteristics of a metal
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define metalloid
a chemical element that forms a simple substance having properties intermediate between those of a typical metal and a typical nonmetal.
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how many metalloids are there?
6
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list the metalloids
boron, silicon, germanium, arsenic, antimony and tellurium
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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
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elements exist as or
atoms, molecules
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what is the symbol for Hydrogen?
H
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what is the symbol for Helium?
He
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what is the symbol for Lithium?
Li
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what is the symbol for Beryllium?
Be
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what is the symbol for Boron
B
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what is the symbol for Carbon?
C
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what is the symbol for Nitrogen?
N
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what is the symbol for Oxygen?
O
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what is the symbol for Fluorine?
F
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what is the symbol for Neon?
Ne
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what is the symbol for Sodium?
Na
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what is the symbol for Magnesium?
Mg
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what is the symbol for Aluminium?
Al
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what is the symbol for Silicon?
Si
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what is the symbol for Sulphur?
S
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what is the symbol for Chlorine?
Cl
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what is the symbol for Argon?
Ar
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what is the symbol for Potassium?
K
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what is the symbol for Calcium?
Ca
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what is the symbol for iron?
Fe
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what is the symbol for mercury?
Hg
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what is the symbol for silver?
Ag
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what is the symbol for gold?
Au
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what is the symbol for copper?
Cu
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what is the symbol for lead?
Pb
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what is the symbol for nickel?
Ni
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what is the symbol for tin?
Sn
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what is the symbol for platinum?
Pt
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What is Sn the chemical symbol of?
Tin
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What is Pb the chemical symbol of?
Lead
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What is Hg the chemical symbol of?
Mercury
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What is Ag the chemical symbol of?
Silver
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What is K the chemical symbol of?
Potassium
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How do elements get their symbols?
It often derived from the scientific name, but can also be from the Latin name
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What is the formula for water?
H₂O
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What is the formula for carbon dioxide?
CO₂
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What is the formula for table salt?
NaCl
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Using the following formula how many atoms are there on each side?
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
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Using the following formula how many atoms of carbon are there on each side?
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
6
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Using the following formula how many atoms of hydrogen are there on each side?
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
12
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Using the following formula how many atoms of oxygen are there on each side?
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
18
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Is this formula balanced?
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
Yes
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is this formula balanced?
HCl + CaCO₃ → CaCl₂ + H₂O + CO₂
If not, balance the equation
No
2HCl + CaCO₃ → CaCl₂ + H₂O + CO₂
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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.
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What do compounds exist as?
Molecules
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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.
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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.
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Give an example of a physical change
An example of a physical change is the melting of ice into water.
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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)
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The formula for photosynthesis is:
6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂
What are the reactants in this formula?
Carbon dioxide, water and energy
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The formula for photosynthesis is:
6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂
What are the products in this formula?
glucose and oxygen
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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.