Atomic Structure & The Periodic Table Flashcards
Element
A substance that cannot be broken down into two or more different substances
Atom
Smallest uncharged particle of an element
Compound
Made of two or more elements chemically joined together
Ion
Charged atom or group of Atoms
What is the structure of an atom?
It has a small, central , positively charged nucleus (protons + neutrons) with electrons orbiting.
What is the relative mass of a proton ?
1
What is the relative mass of a neutron?
1
What is the relative mass of an electron?
1/1840
What is the relative charge of protons?
+1
What is the relative charge of neutrons?
0
What is the relative charge of electrons?
-1
What is meant by the term atomic number?
Is the number of protons in the nucleus of an atom of that element
What is meant by the term mass number?
The sum of the number of protons and neutrons in a nucleus of an atom
How do we determine the number of each sub atomic particle from atomic number or mass number?
Atomic Number = Number of Electrons
Mass Number = Neutrons + Protons
Number of Neutrons = Mass Number - Atomic Number
Define the term Isotope
Are atoms of the same element that have the same number of protons but different number of neutrons
Define relative isotopic mass based on the 12c scale
The mass of an atom of that isotope divided by 1/12 the mass of a carbon-12 atom
Define relative atomic mass (Ar)based on the 12c scale
The weighted average mass of an atom of that element divided by 1/12 the mass of a carbon-12 atom
Define relative molecular mass (Mr)?
Of an element or a compound is the average mass of a molecule of that element or compound divide by 1/12 the mass of a carbon-12 atom
When should the term Relative formula mass be referred to ?
Used for compounds with giant structures
What does the letter Z represents?
The atomic number of an atom
What does the letter A represents?
Mass Number
What is the relative atomic mass quoted on the periodic table table showing ?
The weighted average of all the isotopes.
For each isotope what can the mass spectrometer measure?
m/z value + abundance
How do you calculating the relative atomic mass from relative abundance of isotopes from mass spectrometry
R.A.M = Σ ( isotopic mass x % abundance) / 100
If two electrons are removed from a particle forming a 2+ ion… what would the m/z value be?
Half the mass
Predicting mass spectra for diatomic molecules like chlorine
- Identify the peaks
- The higher m/z peaks corresponds to the addition of the molecules
- Apply the RAM formula divide by 2