CT2 Flashcards
What is the electronic charge of a proton
+1
What is the electronic charge of an electron
-1
What is the electronic charge of a neutron
0
What is the relative mass of a proton
1
What is the relative mass of an electron
~0 (1/1800)
What is the relative mass of a neutron
1
What was Daltons atomic theory
- All matter is made of atoms.
- Atoms are very small.
- Atoms can’t be broken down, created, or destroyed.
- Each element has its own type of atoms.
Where did the word atomic come from
A - tomos
= no breakdown
How were subatomic particles proven to be real
Their existence was proven by the cathode ray experiment (electrons).
Where are subatomic particles found
Inside the atom (particles smaller than the atom).
Why is the charge of an atom 0
An atom always has the same number of protons and electrons which cancels out the charge.
Where are electrons found
Electrons orbit the nucleus at set distances (and at set energy levels) called electron shells.
What is the atomic number
The number of protons (the smaller number).
What is the mass number
The number of protons and neutrons (the bigger number).
Isotopes
Atoms of the same element but with a different number of neutrons.
RAM
Relative Atomic Mass
Ar (not the element)
- The mean mass of an atom of an element compared to 1/12 of the mass.
- Takes into account all the isotopes of that element.
Formula to calculate RAM
((Abundance of isotope 1 x mass of isotope 1) + (Abundance of isotope 2 x mass of isotope 2)) divided by 100
How did Mendeleev arrange his periodic table (in the 1870s)
- In order of atomic mass and groups.
- Grouped by their properties.
- Left spaces for undiscovered elements.
How is the modern periodic table arranged
In order of atomic number.
What did Moseley do
Used X-ray analasis to show that elements properties are linked to atomic numbers. = number of protons.
Periods
(rows) in order of atomic number.
Groups
(vertical columns) in which elements have the same properties.
How many electrons can the first shell hold
up to 2
