Structure Of The Atom Flashcards
What is the Atomic Number? (3)
- Unit = Z
- Number of Protons
- Decides the element
What is the Mass number? (3)
- Unit = A
- Number of Protons & Neutrons
- Neutrons = A - Z
X is the symbol of an element. What goes on top and what on the bottom? (2)
- Mass number on top (A)
- Atomic number on bottom (Z)
What are Isotopes? (2)
Isotopes are different atoms of the same element with same atomic number but different mass numbers.
Relative Atomic mass? (2)
- (Ar)
- Is a number that compares the average mass of an atom to the mass of the C-12 atom taken to be 12 units.
What is the formula for (Ar)? (1)
Ar = (%/100 x Isotope) + (%/100 x Isoptope)
When given the Ar, how to do you find percentage of the Isotopes? (1)
(x/100 x Isotope) + (100-x/100 x Isotope) = Ar
What is an ion?
What is a cation?
What is an anion?
(3)
- An ion gains or loses electrons
- A cation is when the ion is positively charged
- An anion is when the ion is negatively charged
Standard mass?
Carbon ( 12 units)
Therefore Hydrogen (1) = 1/12 units
Ar (H) = 1 unit
What is an orbital?
An orbital is a three dimension region around the nucleus where there is a high probability of finding an electron with a certain amount on energy.
S- orbital?
P- orbital?
(2)
- S orbital is spherical
- S orbital has less energy
- 1 orbital
- P orbital is tear drop shaped
- P orbital has more energy
- P orbital has 3 orbitals
What can an orbital accommodate? (1)
An orbital can accommodate 2 electrons with opposite spin.
Valence electron? (1)
Electrons that occupy that occupy the outer most energy level
Why are the valence electrons important? (2)
- First to interact with other electrons
- Electrons involved in bonding
What are the Core electrons? (2)
- Electrons that occupy the inner energy levels
- Shield the valence electrons from the nuclei’s attraction
Energy level=
Valence electrons=
(2)
- e.l = period
- v.e = group A
Atomic Diameter? (2)
- How far the electrons are positioned from the centre
- no definite limit
Radius of an atom? (2)
- Found by measuring the distance between the 2 nuclei of the touching atoms
- Then halving the distance
Why does the atom size get bigger when there are more electron shells? (2)
- more energy levels
= more shielding
What is the Shielding Affect? (1)
- When the inner electrons are shielding the outer electrons
More Radius = (1)
More shielding
When does the atom size get smaller? (2)
- When the valence electrons fill up the outer energy levels
- more energy = attraction
= smaller
What is Ionisation Energy? (2)
The minimum amount of energy required to remove an electron from an atom in the gas phase
First and second Ionisation energy? (2)
Removing the first electron
Removing the second electron
Why are Valence electrons generally easy to remove? (1)
Least attracted to the nucleus
2 things affecting Ionisation energy. (2)
- Atomic radius (if small, higher Ionisation energy (if valence electrons fill up the outer energy levels))
- Charge ( higher positive charge- harder to pull away
When does Ionisation energy increase?
When does Ionisation energy decrease?
(2)
- increase = as move across period
- decrease = as move down a group
Protons and Neutrons are collectively known as? (1)
Nucleons
