Lecture 5-10 Flashcards
Define “atom”
The smallest identifiable unit of an element.
Who were the two men who conceived of or discovered the atom?
Democritus with the theory of atomos.
John Dalton revived it with the Atomic Theory.
What three things does the Atomic Theory postulate?
- Each element is composed of atoms.
- All atoms in an element have the same mass and other properties that distinguish them from other elements.
- Atoms combine whole number ratios to form compunds.
In what order were the three parts of an atom discovered?
Electron (Thomson), proton (Rutherford), and neutron (Chadwick.)
What is the weight of one amu (atomic mass unit)?
It is 1/12 of the mass of a carbon-12.
What are the charges of the proton, electron, and neutron?
Proton is positive.
Electron is negative.
Neutron is neutral.
What is the atomic number (Z)?
It is the number of protons and neutrons in the element. In a neutral atom it will also be the number of electrons.
Explain the chemical symbol.
An abbreviation used to denote an element. The first letter is always capitalized and the second letter, if any, will be lower case.
How many named and unnamed elements are there?
There are 118 named elements and 1 unnamed element.
What is one mole (M)?
12g of carbon.
Give the formula for average mass.
(% of abundance/100)(mass of isotope 1)+(% of abundance/100)(mass of isotope 2)…+etc.
What is the law of constant composition?
All samples of a given molecule have the same properties of atoms that make up the molecule.
Name the diatomic molecular elements.
H2, N2, O2, F2, Cl2, Br2, and I2.
What is the difference between molecular and ionic compounds?
An ionic compound consists of a metal and a nonmetal bonded together.
A molecular compound is two nonmetals bonded together.
How do you write an ionic compound formula?
-The sum of charges add up to zero (in a stable compound.)
-The metal (cation) is written first and then the nonmetal (anion.)
~The 1+ elements: Li, Na, K, Rb, Cs, Fr, Ag
~The 2+ elements: Mg, Ca, Sr, Ba, Ra, Cd, Zn
~The 3+ elements: Al
~The 1- elements: F, Cl, Br, I
~The 2- elements: O, S,
~The 3- elements: N, P
