SA 2 Flashcards
(37 cards)
In the line emission spectrum of hydrogen, which of the following electron transitions would not appear?
a. n = 3 to n = 1
b. n = 3 to n = 4
c. n = 4 to n = 1
d. n = 3 to n = 2
b. n = 3 to n = 4
In which energy level can we see visible lines
n = 2
What is meant by a ‘metallic character’?
Defined as how easily an atom can lose an electron
What did Bohr conclude about the structure of the atom from analysis of this spectrum?
Electrons move around the nucleus of the atom in certain fixed paths.
Which of the following has the greatest metallic character?
a. Cl
b. Na
c. Al
d. C
b. Na
What is the approximate bond angle between Cl–N–Cl in NCl3?
109.5°
What intermolecular molecules does SO2 have?
dipole-dipole and dispersion forces
1s2 2s2 2p6 3s2 3p6 3d4 5s1
(i) Identify the atom.
(ii) Write the ground state electron configuration of the atom.
(iii) Explain what is meant by the term ‘ground state’ for the electron configuration.
i. Vanadium
ii. 1s2 2s2 2p6 3s2 3p6 4s2 3d3
iii. ground state = the lowest possible electron configuration (lowest energy level)
Draw the Lewis structure and Identify the molecular shape of:
(i) SiF4
(ii) SF4
google lol
What is the main concept of the Bohr model?
Electrons occupy definite orbits and each orbit has a specific amount of energy - aka quantised. Orbits closer to the nucleus have smaller amounts of energy, to go to a higher energy level, it needs to absorb energy, and vice versa (to go to a lower energy level, emit energy). The amount of energy absorbed or emitted is fixed.
How do atoms gain energy?
One way is to pass an electric current through an enclosed sample of a gas. Another way is to supply heat energy using a flame (flame tests). Then, the light emitted can be passed through a prism to separate the different wavelengths of light. Only discrete lines of certain wavelengths appear, the spectrum is called a line emission spectrum.
What was the problem with the Bohr model?
That it fails for any multi-electron system.
The Bohr model is only successful for atoms that have a single electron, energy levels containing more than one atom cannot be calculated successfully.
What is the quantum mechanical model?
A model made by Schrödinger, which accurately described the behaviour of the electron in a hydrogen atom. (note that its not a ‘model’, but a s p f d thing)
What is the Pauli Exclusion Principle?
That no two electrons can have the same set of quantum numbers - every orbital has a max of 3 electrons, and can be unoccupied, occupied by 1, or occupied by 2.
What is the difference between the Bohr model and the Quantum mechanical model?
In the Bohr model, the pathway of the electron was fixed into circular orbits. The quantum mechanical model states that the electrons do not orbit the nucleus but instead travels in specific patterns referred to as electron clouds.
What is the Aufbau Principle?
Boxes. That electrons occupy the lowest energy to the highest. s then p then d then f.
What is Hund’s Rule?
That orbitals of equal energy are occupied by one electron before any orbital is occupied by a second electron, maximizing the number of unpaired electrons. Boxes.
What elements are the exceptions to the ground state configurations?
Cr = 1s2 2s2 2p6 3s2 3p6 4s1 3d5
Cu = 1s2 2s2 2p6 3s2 3p6 4s1 3d10
Write 1s2 2s2 2p6 3p1 in its excited state
1s2 2s2 2p6 4p1
What are these called?
Group 1, 2, 17, 18
Group 1 are known as the alkali metals
Group 2 is also known as alkali earth metals
Group 17 is also known as the halogens
Group 18 is also known as the noble gases
What is an isoelectronic species?
Compare the sized of:
O2-, F-, Ne, Na+ and Mg2+
Elements that have the same number of electrons (Li+ and Be2+), they will have the same amount of shielding but different number of nuclear charge (more nuclear charge = smaller)
Mg2+ < Na+ < Ne < F- < O2-
What is ionisation energy?
State the first ionisation energy equation
The energy required to remove an electron from an atom in its ground state
X(g) → X+(g)+ e-
What is electronegativity and what is its difference with electron affinity?
The ability of an atom to attract electrons in a bond when the atom is part of a compound.
- different from electron affinity because electron affinity is the actual amount of energy released when an atom gains an electron. Electronegativity is not measured in energy units, but is a relative scale, where the elements are compared to each another.
What is the octet rule?
The losing or gaining of an electron to achieve the lowest possible noble gas configuration.
