EL Flashcards
What is atomic number?
The number of protons present in the nucleus of an atom.
What is mass number?
The total number of nucleons (protons and neutrons) present in the nucleus of an atom.
What is relative atomic mass?
The mean weighted mass of an atom of an element compared to 1/12th of the mass of carbon-12.
What is relative molecular mass?
Relative molecular mass is the mean weighted mass of a molecule compared with 1/12th the mass of an atom of carbon-12.
What is relative formula mass?
Relative formula mass is the sum of the mean weighted masses of all atoms in the formula of a compound compared with 1/12th the mass of an atom of carbon-12.
What is relative isotopic mass?
Relative isotopic mass is the mass of an isotope compared with 1/12th the mass of an atom of carbon-12.
What is the mole?
A mole = the amount of substance containing as many particles as there are atoms in 12g of carbon-12.
1 mole = 6.02 x 10^23 items = Avogadro constant
What is an ionic equation?
An ionic equation is an equation in which only the non-spectating ions are shown.
How is percentage yield calculated?
Percentage yield is calculated by dividing the actual yield by the theoretical yield and multiplying by 100.
How is percentage composition by mass calculated?
Percentage composition = (mass of desired substance / total mass) x 100
How is a standard solution prepared from a concentrated solution?
- A certain volume of the concentrated solution is added to a volumetric flask to achieve the desired final volume.
- Distilled water is added to the volumetric flask up to the line on its neck.
What are the shapes of s and p orbitals?
s orbitals are spherical, while p orbitals have a dumbbell shape.
What are orbitals?
Orbitals are regions in the space around an atom where electrons are most likely to be found; they can contain a maximum of two electrons.
How are electrons arranged in orbitals?
Electrons fill from the lowest energy orbital first (e.g. they will not fill the fourth shell first).
Electrons will prefer to occupy orbitals by themselves, and will only pair with other electrons if no other lower energy orbitals are available to fill.
How are orbitals filled on the energy level diagram?
Each box on the diagram represents one orbital and each arrow represents one electron.
Why does the 4s orbital fill before the 3d orbital?
The 4s orbital is of a lower energy than the 3d orbital, so it fills up first.
What is the plumb pudding model?
Charge is equally distributed around the atom.
What did the Geiger-Marsden experiment show?
What did the Geiger-Marsden experiment show?
It showed that the atom contained a very small, dense, positive nucleus.
What is fusion?
When two lighter nuclei collide and combine to form a heavier nucleus, releasing energy.
What are the conditions for fusion to happen?
Conditions for fusion include high temperature and pressure.
What is covalent bonding?
In a covalent bond, a pair of electrons is shared between two atoms. Covalent bonds are strong as there is a strong electrostatic attraction between these shared electrons and the nuclei of the bonded atoms.
Why do giant covalent lattices have a much greater melting point than simple covalent molecules?
The covalent bonds between the atoms in a giant covalent lattice are much stronger than the IDIDBS between the simple covalent molecules.
Why are ionic substances only conductive when dissolved?
When ions are in a solid, they are unable to move so they cannot carry charge. Dissolving the solid causes the ions to be mobile, so they are free to carry charge.
