Flashcards in The Structure of Matter Deck (54):
Formed by the chemical union of two or more elements in definite proportions
What is all matter made up of?
Greek for atom, meaning uncut
What is the most widely held theory of atomic structure?
When was the Bohr Atom first proposed?
In 1913 by Niels Bohr
What are the (4) symbolic representations of matter?
1. Medieval Atom (air, water, fire earth
2. Dalton Atom (hooks and eyelits)
3. Thomson atom (pudding)
4. Bohr Atom (orbiting nucleus)
What are protons?
Parts that make up an atom
How big are Protons?
Almost 2,000 times the size of electrons
What is the charge of a proton?
Are all protons identical?
Yes, but each element has it's own characteristic number of protons
Every element must have at least ____ proton.
-Same mass as the proton
-Part that make up an atom
-1,850 times mass of e-
The positively charged nucleus contains most of the _____ of an atom.
What type of charge does an e- have?
1 negative charge
-Extremely small mass
-Orbit the nucleus in specific energy levels/orbits shells
Shells are named according to their distance from the nucleus starting with the letter...
Each shell can only hold a specified maximum number of e-? T/F
Once filled electrons must go into another shell
What are the number of electrons in each shell?
What is the formula for the maximum # of Electrons per shell?
What is the maximum number of e- that can exist in the "P"orbit?
What are the two charged particles in an atom?
Proton & Electron
What is a neutral atom?
The total number of orbital electrons equals the total number of protons in the nucleus
What is the atomic number?
# of protons in the nucleus
What distinguishes each elements from all the other elements?
The atomic number
What is the symbol for atomic number?
Where is the majority of the mass on an atom located?
In its nucleus (protons, neutrons)
What is the sum of the # of protons and neutrons in the nucleus of the atom?
What is the symbol for Mass Number?
What is the shorthand notation used to denote a specific element or isotope of an element?
What is an isotope?
Atoms of the same element having different mass numbers
What specifically about isotopes makes them different?
The number of neutrons in the nucleus
What are isobars?
Two or more atoms with the same atomic weight (mass #) but with different atomic numbers
Two or more atoms with the same molecular formula, but different physical and chemical properties
What is an example of an Isomer?
Two or more atoms with the same # of neutrons, but having different # of protons in the nucleus...
What is a Z#?
What is an A#?
What is binding energy?
Energy required to remove an e- from a particular shell and beyond the range of the nucleus
The closer a shell is to the nucleus the _____ the binding energy>
The higher the Z#, the _____ the binding energy
On the periodic table, what is the group # (roman numeral?)
# of electrons in the outer shell
On the periodic table, what is the period #?
# of electron shells
How is chemical behavior determined?
By the property of elements that is determined by the number of e- in the outer shell
What is the octet rule?
An atom tends to be chemically stable when its outer shell contains exactly 8 e-
What is the only exception to the octet rule?
Helium, it has 2 e- in the outer shell
What are ions?
Atoms that either lose or gain e-
What is a valence?
Number of e- lost, gained or shared by an atom in chemical combination
What are bonds?
Two or more elements are joined together by one of several different types of chemical bonds
What are ionic bonds?
-Bonds between 2 ions
-Trasnfer of e- between the elements
What is a covalent bond?
Sharing of e- between 2 or more atoms
What does ionization mean?
The process of converting atoms to ions
How does ionization happen?
Exclusively by the addition or removal of outer shell e-