2- Atoms, Ions and Compounds Flashcards
what is the abbreviation of a proton?
p+
what is the abbreviation of a neutron?
n
what is the abbreviation of a electron?
e-
What is the relative charge of a proton?
+1
What is the relative charge of a neutron?
0
What is the relative charge of a electron?
1-
What is the relative mass of a proton?
1
What is the relative mass of a neutron?
1
What is the relative mass of a electron?
1/1836
What subatomic particles are present in the nucleus?
Protons and neutrons
Why are neutrons in the nucleus?
To overcome the electrostatic repulsion of the protons in the nucleus. Otherwise protons would break apart. Neutrons act like glue that holds the nucleus together
When does an atom become radioactive?
When there are not enough neutrons to overcome electrostatic force, not stable to maintain, protons split apart
What is the overall charge of an atom?
Zero. Total positive charge from protons is balanced out by the total negative charge of electrons
What is the atomic number equal to?
Proton number
Where are electrons found?
energy levels
What is an isotope?
Atoms of the same element with a different number of neutrons and a different masses
Do isotopes of the same element have the same chemical properties?
Yes, all have the same number of electrons. neutron number has no effect on reactions of element. ASll isotopes of a element react in the same way
Do isotopes of the same element have the same physical properties?
No, different neutron number so different physical properties
How do you work out the mass number?
Number of protons + number of neutrons
How do you work out the number of neutrons?
Mass number - Atomic (proton) number
What is an ion?
A charged atom. The number of electrons is different from the number of protons
What is a positive ion called?
Cation
-fewer electrons then protons
What is a negative ion called?
Anion
-more electrons then protons
What is relative isotopic mass?
the mass of an isotope relative to 1/12th the mass of an atom of carbon-12
What is the mass of a carbon-12 isotope?
1.992646538 x 10^-26 kg
- 12 atomic mass units (12u)
- 1u = 1/12th of an atom of carbon-12
-1u = approx the mass of a proton or neutron
What is relative atomic mass?
The weighted mean mass of an atom of an element relative to 1/12th the mass of an atom of Carbon-12
What does the weighted mean mass take into account?
-percentage abundance of each isotope
-relative isotopic mass of each isotope
What is mass defect?
The difference between the actual mass of an atom and the sum of the masses of its protons, neutrons and electrons.
The missing mass is the binding energy holding the atom together
How do you work out the percentage abundances of the isotopes in a sample of an element?
mass spectroscopy
How does the mass spectrometer work?
- The same is placed into the mass spectrometer
- The sample is vaporised and turned into a gas
- Sample is ionised to form positive ions
- Ions are accelerated. heavier ions move slower and are more difficult to deflect then lighter ions, so ions of each isotope are separated
- Ions are detected on a mass spectrum as a mass-to-charge ratio m/z. Each ion reaching the detector adds to the signal, so the greater the abundance, the larger the signal
How do you work out the mass-to-charge ratio (m/z)?
m/z = relative mass of ion / relative charge of ion
What is a binary compound?
An compound that is made of two elements only
How do you work out the name of a binary compound?
-use the name of the first element but charge the ending of the second element to -ide
-for ionic compounds, metal ion always comes first
What is the charge of Ag ions?
1+
What is the charge of Zinc ions?
2+
What are polyatomic ions?
Ion formed of mor then 1 atom bonded together with an overall charge
What are the formula and charge of nitrate?
NO3-
What are the formula and charge of carbonate?
CO3 2-
What are the formula and charge of sulfate?
SO4 2-
What are the formula and charge of hydroxide?
OH-
What are the formula and charge of ammonium?
NH4+
What are the formula and charge of nitrite?
NO2-
What are the formula and charge of hydrogencarbonate ?
HCO3-
What are the formula and charge of manganate(VII)?
MnO4 -
What are the formula and charge of sulfite?
SO3 2-
What are the formula and charge of dichromate(VI)?
Cr2O7 2-
What are the formula and charge of phosphate?
PO4 3-
What are the naming rules?
-numbers in subscript
-ion charges not in final formula as compound is neutral
-brackets used for polyatomic ions
What are the rules when balancing equations?
-not change any of the chemical formula
-balancing numbers go in front of the chemical formulae and on the line
-the same amount of atoms of each element on each side of equation
What are diatomic molecules? And which are they?
Two atoms bonded together
H2 N2 O2 F2 Cl2 Br2 I2
P4 S8
