Chem Quiz 1 Flashcards
What did Democritus say in 300 B.C?
Atoms are indivisible, matter can be divided.
What did Dalton say in 1808?
- All matter is made up of tiny particles (atoms). 2. Atoms cannot be created,destroyed, or subdivided in chemical changes. 3. All the atoms of one element have the same properties (mass and size). 4. Atoms of different elements combine in specific proportions to form compounds.
Who created the model of the plum pudding and when?
JJ Thomson in 1904.
Describe the model of plum pudding.
The Plum Pudding Model is a model of atomic structure. Thomson had discovered that atoms are composite objects, made of pieces with positive and negative charge, and that the negatively charged electrons within the atom were very small compared to the entire atom. small negative particles in a positive sphere.
What did Rutherford do in 1911?
Performed the gold foil experiment and found out that both the nucleus and electrons are tiny. Most of the atom is empty space.
What did Rutherford do with the info gained from the gf experiment?
He created a new model of an atomic structure. With the electrons orbiting around the positive nucleus . Most of the atom is just empty place because most of the mass is in the tiny nucleus.
In standard atomic notation, what do the numbers around the element symbol mean?
Top left: mass# Bottom left: atomic #
What is an isotope?
Two or more atoms that have the same number of protons but not neutrons.
What do you call two atoms that have the same atomic number but a different mass number?
Isotopes
When you write an element like this: C-12 What does the 12 indicate?
The mass number.
What is the mass number?
The number of protons and neutrons.
What is the atomic number?
The number of protons.
What is a radioisotope?
An isotope that has an unstable nucleus.
What are the three principal uses of radioisotopes?
- Diagnosis and treatment of illnesses. 2. Dating fossils. 3. Smoke detectors.
What is the average atomic mass?
The weighted average mass of the isotopes of an element.
How are average atomic masses determined?
By using a mass spectrometer.
How do mass spectrometers work?
After ionization, acceleration, and selection of a single velocity, particles move into a mass spectrometer region where the radius of the path and the position on the detector is a function of the mass. They are passed through an electric field, then through a magnetic field.
What is the formula for average atomic mass?
a.a.m=(m1)(f1) + (m2)(f2) f= frequency (decimal) m= mass (in u)
What is the octet rule?
Atoms with a full outer shell (8 valence electrons) are very stable.
Why are noble gases not reactive ?
Because they have a full outer shell. No electrons need to be gained or lost to make them complete.
What is the atomic radius?
Size of an atom.
In what pattern does the periodic table follow in terms of atomic radii?
To the left and downwards= increasing in size.
What is ionization energy?
The energy required to remove a single electron from an atom.
In what pattern does the periodic table follow in terms of ionization energy of the elements?
To the right and upwards= increasing in ionization energy.
What is the periodic law?
Recurring patterns can be seen in the physical and chemical properties of the elements when the are arranged in order of increasing atomic number.
How do NON-metals obey the octet rule?
Non-metals either: 1. gain electrons (become anions) 2. share electrons (covalent bonding)
What is electron affinity?
A change in energy that occurs when an electron is added to the outer energy level of an atom to form a negative ion. The neutral atom’s likelihood of gaining an electron
In what pattern does the periodic table follow in terms of electron affinity?
To the right and upwards= increasing in electron affinity (likelihood of gaining an electron). Noble gases are not included.
What are the 3 kinds of Binary compounds (2 elements)?
- Ionic 2. Covalent 3. Acids
What defines an ionic binary compound?
A metal and non-metal completing each other.
What defines a binary covalent compound?
A non-metal and a non-metal.
What defines an acid?
Hydrogen and (usually) a halogen.
What is the charge and name of: NO3?
nitrate 1-
What is the charge and name of: HCO3?
bicarbonate 1-
What is the charge and name of: ClO3?
chlorate 1-
What is the charge and name of: OH?
hydroxide 1-
What is the charge and name of: SO4?
sulfate 2-
What is the charge and name of: CO3?
carbonate 2-
What is the charge and name of: PO4?
phosphate 3-
What is the charge and name of: NH4?
ammonium 1+
How many Os are added/subtracted when the suffi/prefix of the polyatomic ion is: ATE
0
How many Os are added/subtracted when the suffi/prefix of the polyatomic ion is: PER–ATE
+1
How many Os are added/subtracted when the suffi/prefix of the polyatomic ion is: ITE
-1
How many Os are added/subtracted when the suffi/prefix of the polyatomic ion is: HYPO–ITE
-2
What is the formula for density?
mass(g)/volume(cm3)
What did Bohr do in 1914?
Created another atomic model.
What did the Bohr model of the Hydrogen Atom show?
It indicated regions where electrons are likely to be found. However, it could not predict light spectra (except for Hydrogen).
What pattern can be noticed with the densities of each period?
They become higher.
