Chemistry Flashcards by Z !

What is an element?

Everything listed on the periodic table is an element.

Elements are the smallest unit of of matter that still has the properties of that element.

(eg. one copper atom has element properties, half of it doesn’t have the same)

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What is ____ made of?
Element?
Molecule?
Compound?

NEW(ish) INFO

Elements are made of 1 atom.
Molecules are made of 2 atoms of the same element.
Compounds are made of 2 or more elements, and 2 or more atoms.

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What is a chemical change?

Chemical changes are when the arrangement of atoms in compounds changes to form NEW compounds, through the exchange of electrons.

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What is a physical change?

Physical changes are when the space between atoms or how fast they are moving changes. We can usually see this as a CHANGE OF STATE.

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What is it called when a solid becomes a liquid?

What is is called when a liquid becomes a solid?

Solid to liquid = melting

Liquid to solid = freezing

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What is it called when a gas becomes a liquid?

What is is called when a liquid becomes a gas?

Gas to liquid = condensing

Liquid to gas = evaporating

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What is it called when a solid becomes a gas?

What is it called when a gas becomes a solid?

Solid to gas
& Gas to solid = Sublimination

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How are ions formed?

An atom gains or loses an electron to form an ion.

ALWAYS REMEMBER BRACKETS AND SIGN

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How do we know what element it is from the Bhor diagram?

The number of protons equals the number of electrons, equals the atomic number for neutral elements.

(Electrons are same amount as periodic table element)

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What is it called when a metal loses electrons?

What is it called when a metal gains electrons?

A metal loses electrons and becomes a cation. (Cations are PAWsitive)

A metal gains electrons and becomes an anion. (Anions are negative, onions make you cry, which is bad)

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What do Bohr diagrams show?

Bohr diagrams show how many electrons appear in each shell around an atom.

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What are electrons in the outermost shell called?

Electrons in the outermost shell are called valence electrons.

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How many electrons are in each shell of a Bohr diagram?

There is a maximum of TWO electrons in the first shell, EIGHT in the 2nd shell, and EIGHT in the 3rd.

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What is the trend with columns in the periodic table?

All elements in the same column of the periodic table react the same way.

(Have the same number of valence electrons)

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What is an ionic bond?

Ionic bonds form when electrons are TRANSFERRED from METALS to NON-METALS, forming positive and negative ions.

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What is a covalent bond?

Covalent bonds are formed when electrons are SHARED between two or more NON - METALS

What are Lewis diagrams?

They show only the valence electrons and are used to represent ions.

Count the column the atom is in, and put that many valence electrons around the elements symbol

What are positive ions?

What are negative ions?

How do you show ions with a Lewis Diagram?

For positive ions, one electron dot is LOST from the valence shell for each positive charge.

For negative ions, one electron dot is GAINED to each valence shell for each negative charge.

Square BRACKETS are placed around each ion to indicate transfer of electrons. Draw charge to indicate if it has gained or lost.

How do you do Lewis diagrams for ionic BONDS?

Draw the lewis diagram for each element
Transfer the electrons so that each element has a full or empty valence shell
Draw the new ions with a coefficient in front of the brackets if you have more than one

How do you do Lewis diagrams for covalent BONDS?

End of lesson 1

Valence electrons are drawn to show SHARING of electrons.

Draw the lewis diagram for each element
Circle pairs of electrons so that each element has a full valence shell
Draw the new molecule using lines for bonds

What are the prefixes?
NEW (NEED TO MEMORIZE)

1 Mono
2 Di
3 Tri
4 Tetra
5 Penta
6 Hexa
7 Hepta
8 Octa
9 Nona
10 Deca

Steps to name a covalent compound

NOTE: WITH COVALENT YOU DON’T REDUCE

Write the prefix for how many there are of the first element
Write the name of the first element
Write the prefix for how many there are of the second element
Write the name of the second element
Change the end of the second element name to “-ide”

Steps to writing a covalent compound (symbols)
NOTE: WITH COVALENT YOU DON’T REDUCE

Write the symbol for the first element
Use the prefix before that element in the name to determine the subscript that follows the symbol
Write the symbol for the second element
Use the prefix before that element in the name to determine the subscript that follows the symbol

Summary: subscript after symbol based on prefix

Steps to naming an ionic compound
Note: WITH IONIC, WE DO REDUCE

Write the name of metal first

If the metal is a transition metal, write a roman numeral in brackets after its name to show its charge

Write the name of the non-metal

If the non-metal is a single element change the ending to “-ide”
If the non-metal is a polyatomic ion do not change its ending

Steps to writing an ionic compound:

1. Write the metal and its charge as a power - If the metal is from the transition metals it’s charge is the roman numeral 2. Write the non-metal and its charge as a power - If the non-metal is a polyatomic ion use the polyatomic ion chart to find the charge 3. Cross charges - If the non-metal is a polyatomic ion add brackets around it - If the two subscripts can be reduced (like 2 and 4 reduce to 1 and 2) then reduce them Summary: metal first, cross charges, add brackets for polyatomic, reduce

What are Roman Numerals?

1 - I 2 - II 3 - III 4 - IV 5 - V 6 - VI 7 - VII 8 - VIII 9 - IX 10 - X

What are the charges of the elements on the periodic table? End of lesson 2

Column 1 = 1+ Column 2 = 2 + *Skip Transition metals* Column 3 = 3+ *Skip column 4 (starts with carbon)* Column 5 = - 3 Column 6 = -2 Column 7 = -1 Column 8 = 0

In a chemical reaction, what are the original, and the new substances called?

The original substance(s), called REACTANTS, change into new substance(s) called PRODUCTS.

What is the Law of Conservation of Mass?

The mass of the reactants equals the mass of the products.

How are states of matter represented in chemical reaction? What if we can't tell what state it is?

Solid (S) Liquid (L) Gas (G) Aqueous - Substance dissolved in water (Aq) If metal or ionic, or more than two elements, guess solid.

What are some strategies for balancing equations?

- Balance single elements last - Balance one element at a time - Only add coefficient, NEVER change subscript - If H and O appear in more than one place, attempt to balance them last *(Hard to remember)* - Polyatomic ions can be balanced as one thing if they stay together - Each time you balance an element, the next element you should balance is one that was attached to the previous element - Always double check your work.

What are the types of reactions and their formulas?

Synthesis - X + Y = XY Decomposition - XY = X + Y Single Replacement - AB + C = AC + B Double Replacement - AB+CD=CB+AD Combustion - ? + O2 = CO2 + H2O Neutralization - Acid + Base = ionic + H2O + compound +(sometimes also CO2)

How do you know if something is an acid or a base? End of lesson 3

- Covalent = likely to be acid **- Acid if it has H - Ionic = likely to be base **- Metal + OH = base

What are the three things needed for a reaction to happen?

1. Reactants must collide 2. Reactants must have greater energy than activation energy 3. Reactants must be in correct orientation

Why do they need sufficient energy for reactions to occur?

- Atoms have to break their original bonds in order to make the new bonds of the product, requiring energy. - The energy required to break the bonds of reactant molecules is called activation energy

How does temperature affect rate of reaction?

- Increasing temperature causes rare of reaction to increase - Because more particles will have energy greater than the activation energy (energy required to break bonds of reactants) - So there are more successful collisions

How does concentration affect rate of reaction?

- Increasing concentration causes rate to increase - Because more particles in the space means more frequent collisions

How does surface area affect rate of reaction?

- Increasing surface area causes rate to increase - Because more particles are exposed for collisions

How does catalyst affect rate of reaction? End of lesson 4

- Adding catalysts lowers the activation energy, so more particles have time to react - Therefore, the rate gets faster.