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Woodruff- Compounds
Woodruff- Compounds and Bonding
Question | Answer |
---|---|
Compound | a pure substance made up of two or more elements that are chemically combined |
Can a compound be separated by physical means? | No, they cannot |
Compounds contain elements in (changing, definite) proportions | definite |
Compounds look and act like the elements that form them (true or false). | false- they do not look or act like the elements that form them |
chemical formula | shows the kinds of elements and ratios of atoms in a compound |
subscript | small number written after and slightly below the symbol showing the number of atoms of that element |
Absence of subscript means | one atom |
diatomic | 2 atoms of same element |
7 elements that pair up together | N, O, Cl, F, Br, I, H |
What does subscript following group of symbols enclosed with brackets or parentheses mean? (NO3)3 | multiply the subscript inside the parentheses- 3 N and 9 O |
_________determines the way in which an atom will react chemically | electrons in the outermost energy level |
How many electrons do all noble gases have in their outer energy level? | 8 |
Why are most atoms trying to achieve in a chemical reaction? | Gain electrons- 8 to be chemically stable |
What will atoms do in order to complete their valence shell? | gain, lose or share electrons |
ion | charged particle or charged atom due to an atom gaining or losing electrons |
Atoms with 1, 2, or 3 valence electrons will do what with those electrons to achieve a complete octet? | lose |
What type of ions ar formed when electrons are lost? | positive |
What do atoms with 5, 6, 7 valence electrons tend to achieve a complete octet? | gain |
Type of elements that tend to gain electrons | non-metals |
type of ions that are formed when non-metals gain electrons | negative |
Atoms with four valence electrons _____ their electrons | share |
Ionic bond | force of attraction between oppositely charged ions |
When K and Cl combine, _____ is formed | KCl- potassium chloride |
When Ca and F combine, _____ is formed | CaF2- Calcium Fluoride |
When K and S combine, _____ is formed | K2S- Potassium Sulfide |
When Mg and O combine, _____ is formed | MgO- Magnesium Oxide |
When Al and O combine, _____ is formed | A203- Aluminum Oxide |
When Li and N combine, _____ is formed | Li3N- Lithium Nitride |
When Mg and Cl combine _____ is formed | MgCl2- Magnesium Chloride |
Ionic bonds are (weak, strong) | strong |
Ionic bonds have (high, low) melting point | high |
Ionic bonds have (high, low) boiling point | high |
Ionic bonds are (soft, brittle) | brittle |
Ionic bonds are (good, poor) conductors as a solid | poor |
Ionic bonds are (good, poor) conductors if dissolved | good |
covalent bond | bond in which elecrons are shared between atoms (non-metals with non-metals) |
molecule | smallest unit of a covalent compound |
Are ionic bonds (weaker or stronger) than covalent bonds? | stronger |
Two atoms of hydrogen bonds form a molecule by | sharing electrons |
Describe an electron dot diagram for a single molecule of H2. | Both hydrogen molecules share two electrons between them, chemically stable |
diatomic molecules | a molecule made up of two atoms of the same element (di- two) |
Water is a _____ molecule because one end is + and the other end is - | polar |
What is the formula for hydrogen sulfide? | H2S |
What is the formular for hydrogen chloride? | HCl |
What is the formula for ammonia? | NH3 |
What is the formula for methane? | CH4 |
Oxygen number or state | the number that tells how many electrons an atom gains, loses or shares forming a compound |
When writing the formula for a compound, the sum of the oxidation numbers must equal _____. | zero |
Binary compound | compound composed of two elements (bi-two) |
First name of binary compound is | element with a positive oxidation number |
Second name of binary compound is | element with a negative oxidation number |
What ending is used when naming a binary compound? | ide |
When must a Roman numeral be used in naming a compound? | Metals with more than one oxidation number |
You must know _____ about atoms in a compound in order to write the formula for the compound | oxidation state or charge or oxidation number, must be 1:1 ratio |
Prefix for 1 | mono |
Prefix for 2 | di |
Prefix for 3 | tri |
Prefix for 4 | tetra |
Prefix for 5 | penta |
Formula for sulfur dioxide | S02 |
Formula for sulfur trioxide | S03 |
Formula for triphosphorus pentnitride | P3N5 |
Formula for carbon tetrachloride | CCl4 |
Formula for carbon monoxide | CO |
Formula for ammonium sulfate | (NH4)2SO4 |
Hydrated crystal | a crystal that contain water |
Anhydrous | without water |
When hydrated crystals are heated | water evaporates |
Four examples of hydrated crystals | copper II sulfate, concrete, cobalt chloride, sodium dichromate |
Formula for copper II sulfate pentahydrate | CuSO4 5 H20 |