Chem Unit Flashcards
What are the special groups/families found of the periodic table?
- Alkali metals
- Alkaline-earth metals
- Halogens
- Noble Gases
What is a common feature of the Alkali metals and where are they found on the periodic table?
- Group 1
- React with H2O & Hallogens
What is a common feature of the Alkaline-earth metals and where are they found on the periodic table?
- Group 2
- React with H2O
What is a common feature of Halogens and where are they found on the periodic table?
- Group 17
- React with Alkali metals
- Have 7 valence electrons
What is a common feature of the Noble gases and where are they found on the periodic table?
- Group 18
- Unreactive
What does the atomic number mean for atoms?
Atomic number = # of p+
Atomic number = # of e-
When an ion has a negative charge it ____________.
Gains electrons
When an ion has a positive charge it _____________.
Loses electrons
What is a Bohr diagram for an atom?
- Consists of a nucleus (holds protons and neutrons), electrons, and electron shells
- Up to 4 electron shells
- Shell 1: 2 electrons
- Shell 2: 8 electrons
- Shell 3: 8 electrons
- Shell 4: 18 electrons
What is a Bohr diagram for an ion?
Same as atom but with brackets around the diagram, stating the charge.
EX. (diagram)2-
What might an ion do to become “happy/stable”?
May lose shells/rings
What is an energy level diagram?
Consists of up to 5 different levels; 18e-
- Level 5: # of electrons (like 4th electron shell) ___________
- Level 4: # of electrons (like 3rd electron shell) 8e-
- Level 3: # of electrons (like 2nd electron shell) ___________
- Level 2: # of electrons (like 1st electron shell) 8e-
- Level 1: # of protons in nucleus ___________
2e-
___________
36p+
What is an Isotope?
An atom with different numbers of neutrons (which changes the mass #)
How is an isotope written?
Atom name - Mass # (ex. Sulfur - 33)
OR
Mass # \ / \ / \ / / \ / \ Atomic # / \
How do you find the number of neutrons in an isotope? (n)
Subtract the Atomic # from the Mass #
How do you find the number of protons in an isotope? (p+)
Same as the Atomic #
How do you find the number of electrons in an isotope? (e-)
Same as the Atomic #
What is an atom and what is it’s characteristics?
- The smallest fraction of an element that can exist
- Composed essentially of electrons (1 negative charge), protons (1 positive charge), and neutrons (no charge)
- Electrically neutral
What is an Ion?
- An atom that is electrically charged, negative or positive (ex. Sulfur 2-)
Positive ion- Negative ion- Loses electrons Gains electrons
What is the lightest part of an atom?
The electron
What does the placement of an element on the periodic table tell us?
Period (rows) - Signifies the total number of electron shells in an element’s atom (Bohr)
Group (columns) - Represents the number of valence electrons of an element’s atom
What ion does an acid release in water?
H+ (hydrogen)
What ion does a base release in water?
OH- (hydroxide)
What colour does litmus paper change into?
Acid - turns/stays red
Base - turns/stays blue
Neutral - no change
What elements are present in an Ionic compound?
Metals & non-metals
What elements are present in a molecular compound?
Non-metals
What is the state of an ionic compound at room temp.?
Solid
What is the state of an molecular compound at room temp.?
Solid, liquid or gas
Are molecular compounds conductive in water?
No.
Are ionic compounds conductive in water?
Yes.
What would an acid taste like?
Sour.
What would a base taste like?
Bitter.
What are the common solid molecular compounds to know?
Sugar (C6 H12 O6) and wax (C25 H52)
What are the common gas molecular compounds to know?
Carbon dioxide (CO2), Oxygen (O2), Carbon monoxide (CO), Carbon tetrahydride (CO4), Ammonia (NH3), Ethane (C2 H6)
How should you find the state of a ionic compound?
- Solubility table (look at 2nd element and match with 1st element.
Very soluble= (aq) Slightly soluble = (s) PRECIPITATE) - Room temp = solid (s)
- Molten = liquid (l)
- Dissolved in water = (aq)
- Aqueous = (aq)
What are the common liquid molecular compounds to know?
Br (l) and H2O (l)
How should you find the state of a molecular compound?
- Know from experience
- State will be indicated
What needs to be added to a compound’s formula?
A subscript of the state; (ex. (s), (l), (g)
What prefixes should be used for a molecular compound with 7 atoms first and 9 atoms second?
Septa_____ nona_____ide