Chemistry Flashcards
(27 cards)
What is the structure of an atom?
A central positive charge orbited by negative charges of negligable mass.
What particle interacts with an electron to excite it, and what must the requirements of this particle be?
A photon, which needs to be of a specific energy value such that an electron can move up an energy level.
How can a photon’s energy be calculated?
E = hf
What happens to excess energy an electron is supplied with?
It is given as kinetic energy
What happens if an electron falls down an energy level?
It emits energy in the form of a photon with frequency f=E/h
What is the equation to find the electron energy in a hydrogen atom?
E = -k/n^2
Where K is a mix of many constants, and n is a quantum number
What are the 4 quantum numbers and what do they mean?
- The principle quantum number n, representing the energy level at which an electron resides. Greater n values are associated with greater electron energies, and are further from the nucleus as the electrons have enough energy to overcome some of the attraction of the nucleus.
- The orbital angular momentum quantum number L, which indicates the shape of an orbital inside an energy level.
- The magnetic quantum number ml, which indicates the orientation of the orbital L.
- The spin quantum number ms, which indicates the direction in which an electron spins, either being +1/2 or -1/2.
What does Pauli’s Exclusion principle state?
No two electrons can occupy the same space, and as the space in which an electron exists is depicted by its quantum numbers, no two electrons in an atom can have the same quantum numbers.
What is an object’s De Broglie wavelegth, and how can it be calculated?
An object’s de broglie wavelength is the scale at which wave-like interactions become relevant towards understanding the object’s behavior. It can be calculated from λ = h/mv.
What is Heisenberg’s Uncertainity Principle and how is it calculated?
The heisenberg uncertainity principle states that due to an electrons size and velocity, it is impossible to know both its momentum and position with 100% accuracy at the same time. (This is why an electron is treated as a wave/cloud of probability, as treating it as a particle would be near impossible).
It is calculated from ∆p∆q≥h/4π
What are the 4 blocks in the periodic table?
The s, p, f and d blocks.
What is the s block, and what are the properties of elements in the block?
The s block contains elements that only have valence electrons in their s orbitals of their outermost energy level.
The elements in the s block often lose electrons in oxidation, react easily and are soft with low melting points.
What are the properties of s block compounds?
s block compounds are often colourless salts and are very unreactive due to their strong ionic bonds. They are very soluble in water.
How is the electron configuration for an s block element written?
[Element] = [Nobel Gas before]ns^y
Where y is the number of valence electrons in the orbital, and n is the energy level
What is the p block, and what are the properties of elements in the block?
The p block consists of elements with valence electrons in both the s orbital and the p orbital of its energy level. The s orbital will get filled first, and the p orbital second.
Elements in this block often have a variety of effects, with metallic and metalloids being in this block alongside covalent-forming elements.
How is the electron configuration for a p element written?
[Element] = [Nobel Gas Before]ns^2np^y
The s orbital can only hold 2 electrons, and the p orbital will hold the rest of the valence electrons y.
What are the properties of p block compounds?
There are a huge amount of p block compounds so there is little to no possible general trends to be seen.
What is the d block, and what are the properties of elements in the block?
The d block consists of elements with valence electrons in both the s orbital and the d orbital of its outermost energy level. The s orbital will get filled first, and the d orbital second, after this the p orbital is filled, however this element will be in the p block.
Elements in this block are metallic in nature, and have an easy time losing electrons. They have large ranges of stochiometry, with greater cation charges causing more covalent-like bonds.
How is the electron configuration for a d element written?
[Element] = [Nobel Gas Before]ns^2nd^y
The s orbital can only hold 2 electrons, and the d orbital will hold the rest of the valence electrons y.
What is the f block, and what are the properties of elements in the block?
The f block consists of elements with valence electrons in the s orbital, the d orbital and the f orbital of its outermost energy level. The s orbital will get filled first, and the d orbital second, the f orbital third and after this the p orbital is filled, however this element will be in the p block.
These elements in the f block are all metals, and have a greater reactivity than d block metals. They are radioactive and unstable.
What is the shape and size of s orbitals, and how many electrons can they hold?
Are there gaps between s orbitals on different energy levels?
The s orbital is a spherical orbital, with a size depending on the principle quantum number n. It is the smallest orbital, and holds 2 electrons at most.
A 1s orbital is smaller than a 2s which is smaller than a 3s.
On different energy levels, there will be tiny gaps called nodes, in which electrons cannot exist but can jump between.
What is the shape and size of p orbitals, and how many electrons can they hold?
Are they bigger or smaller than s orbitals?
The p orbital is a dumbell-shaped orbital, with a size depending on the principle quantum number n. It holds 6 electrons at most, which causes early p block elements to have 8 valence electrons (with 2 in the s orbital).
A p orbital is larger than an s orbital.
What is the shape and size of d orbitals, and how many electrons can they hold?
Do they have any special quirks?
Are they bigger or smaller than p orbitals?
The d orbital, occuring from the 3rd energy level on, and is the shape of two dumbells stuck together. It can hold up to 10 electrons, causing transition metals to have 12 valence electrons (considering 2 are in the s orbital).
A quirk of the d orbital is that towards the end of the transition metals, an electron will move from the s orbital to the d orbital, and then the next electron will fill the s orbital. This is simply due to the fact that this arrangement is more stable.
A d orbital is bigger than a p orbital.
What is the shape and size of f orbitals, and how many electrons can they hold?
Are they bigger or smaller than p orbitals?
The f orbital is shaped like 3 dumbells together, and can hold up to 14 electrons. They are bigger than d orbitals, and so are the largest orbital shape.
