1.2. The nuclear atom Flashcards

Question

Calculating the energy between quantum levels

Answer 1

Energy change of electron = Energy of photon Energy of photon = hf h - plancks constant f - frequency

Answer 2

Electrons can only change their energy by discrete amounts/ quanta of energy.

Answer 3

The first energy level of an atom. It has quantum number 1. n = 1

Answer 4

The energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous 1+ ions under standard conditions. Energy needed to excite an electron past the convergence limit (it becomes a free electron). Once removed the electron is in the 'n = ∞' energy level-. ## Footnote Same definition but energy required to remove two electrons...

Answer 5

1. An electron in the ground-state becomes excited (eg. by passing a current through the atom → Electrical discharge) 2. This causes the electron to move to a higher energy level 3. It stays in this excited state for a fraction of second. It then falls down to a lower level as it relaxes 4. When doing this it emits a photon (discrete energy) 5. The photon has a specific wavelength, depending on the energy difference between the two energy levels.

Answer 6

Energy levels get closer together (converge) at higher energies) At the limit of this convergence, the lines merge, forming a continuum. Beyond this continuum the electron can have any energy; it is no longer under the influence of the nucleus and is therefore outside the atom. --> Delocalised.

Answer 7

Light is a wave since it can be described by its frequency. Light is made of particles called photons. Both models are needed to explain the characteristics of light. ## Footnote Relates to electrons as they also behave like waves sometimes. (Wave-particle duality)

Answer 8

- Any attempt to locate an electron will disturb its motion. - eg. focusing radiation on an electron to locate it causes it to divert from its path. Heisenbergs uncertainty principle - We can't know where an electron exists at any given moment in time, but we can make a probability picture for where it is likely to be.

Answer 9

A region around an atomic nucleus with a 90% probability of finding an electron. The shape of orbitals depends on the energy of electrons. Electron in higher energy orbital = higher probability of being foudn further from the nucleus ## Footnote Sublevels in energy levels. Each atomic orbital can contain 2 electrons of opposite spin.

Answer 10

Electrons spin on their axis, either in a clockwise (upwards arrow), or anti-clockwise direction (downwards arrow). Electrons with opposite spin can exist in the same area despite their repulsion.

Answer 11

An orbital can only hold two electrons of opposite spin. --> Opposing spin means the electrons don't repel each other.

Answer 12

1 atomic orbital (1s²) | 2 electrons ## Footnote s orbital is shaped like spere.

Answer 13

(2 sublevels, s and p) 1 * 2s atomic orbital (2s²) + 3 * 2p atomic orbitals (2p⁶) | 8 electrons ## Footnote S orbital is shaped like sphere (2s is larger than 1s + electron is likely to be further out). P orbital is shaped like dumbells (along y, x and z axis)

Answer 14

(3 sublevels - s, p and d) 1 * 3s aotmic orbital (3s²) + 3 * 3p atomic orbitals (3p⁶) + 5 * 3d atomic orbitals (3d¹⁰) | 18 electrons ## Footnote Four of the 3d atomic orbitals are made up of 4 lobes centred on the y-axis, x-axis, z-axis. The fifth 3d atomic orbital looks like a pool floatie, with two nodes sandwiching it on the y-axis.

Answer 15

Four sublevels 1 * 4s atomic orbital (4s²) + 3 * 4p atomic orbitals (4p⁶) + 5 * 4d atomic orbitals (4d¹⁰) + 7 * 4f atomic orbitals (4f¹⁴) | 32 electrons

Answer 16

Hydrogen, Helium | 1s² ## Footnote 1st period

Answer 17

Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Flourine, Neon | 2s² 2p⁶ ## Footnote 2nd period

Answer 18

- Depends on atomic number -

Answer 19

Electron orbitals having the same energy levels. Eg. 2s, 2p

Answer 20

3 p orbitals form a p sublevel. A p sublevel and an s sublevel form the second energy level.

Answer 21

Electrons fill atomic orbitals of the lowest available energy level before occupying higher-energy levels. 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p This is essentially the order of the periodic table.

Answer 22

The lowest possible energy level that the atom can occupy. This is the energy state that would be considered normal for the atom.

Answer 23

If more than one orbital in a sublevel is available, electrons occupy different orbitals with parallel spins. So in carbon (1s²2s²2p²)... There are three possible 2p orbitals, instead of having two electrons of opposite spin in the first 2p orbital, there is one electron in the first 2p orbital, and one electron with parallel spin in the second 2p orbital. ## Footnote This is done because it minimises repulsion between electrons. --> less overlap between sublevels. Parallel spins because it leads to lower energy.

Answer 24

Electrons in the outer energy level. Responsible for compound formation.

Answer 25

Total energy level for n=3 is lower than total energy level for n=4. HOWEVER..... Total energy level for the orbital 4s is lower than total energy level for 3d. Therefore 4s gets filled before 3d. HOWEVER.... Filling all of 3d¹⁰ and one electron in 4s is more stable than the alternative. Filling all of 3d⁵ and one electron in 4s is more stable than the alternative.

Answer 26

1s²2s²2p⁶3s²3p⁶3d⁵4s¹ [Ar]3d⁵4s¹ ## Footnote This is done because it is more stable and 3d and 4s are similar in energy levels.

Answer 27

Chromium and copper

Answer 28

1s²2s²2p⁶3s²3p⁶3d¹⁰4s¹ [Ar]3d¹⁰4s¹ ## Footnote This is done because it is more stable and 3d and 4s are similar in energy levels.

Answer 29

Atoms always lose electrons from the outer sub-level first (highest quantum number). Eg. all transition elements can form 2+ ions since 2 electrons can be removed from 4s²

Answer 30

First two elements of a period eg. Li, Be

Answer 31

Last 6 elements in a period. eg. Al, Si, P, S, Cl, Ar

Answer 32

Transition element block ## Footnote 10 elements across

Answer 33

Lanthanides and actinides

Answer 34

- Nuclear charge (attraction of the nucleus to the electron, no. of + protons - Z) * As nuclear charge increases across a period, the ionisation energy increases (greater nuclear attraction) - Electron shielding (electron-electron repulsion between energy levels) * Full energy levels 'shield' valence electrons form the nuclear attraction of the nucleus. * This decreases IE - Electron spin repulsion is when an electron is added to an atomic orbital in a half-filled sublevel. * O = 4 electrons in 2p (hund's rule) --> 2 electrons in one orbital * Technically opposite electron spins in one orbital allow them to coexist, but they still repel each other slightly → This makes it unstable → Easier to lose an electron → Lower ionisation energy.) * This makes it easier to lose electrons --> IE decreases. - Atomic radius inc. = smaller attraction between nucleus + valency electrons --> IE dec.

Answer 35

Increases. Nuclear charge increases --> IE inc. Energy shielding stays constant (1 energy shield)

Answer 36

Be - 1s²2s² B - 1s²2s²2p¹ - Easier to remove an electron from 2p sublevel --> Further from nucleus. 2p is higher energy level

Answer 37

N = 1s²2s²2p³ O = 1s²2s²2p⁴ Electron-Electron repulsion. Nitrogen has 1 electron in each orbital. In oxygen there are two electrons in the first orbital (electron-electron repulsion) --> Less stable than oxygen. --> Easier to lose it --> Dec. IE.

Answer 38

Going down a group, means electron shielding is added each period. This decreases the nuclear attraction (attraction between valence electrons and the nucleus). This decreases IE.

Answer 39

First ionisation energy = Na_{(g) Na⁺}_(g)(-)+_{(g) Na²⁺}_(g)(-)

Answer 40

Na = 1s^{22s^{22p^{63s^{1

First electron is removed at a 500 kJmol^{-1

Second electron is removed at 5000 (much higher bcecause the energy shield between 2p^{63s^{1 has been removed.}}}}}}}

1.2. The nuclear atom Flashcards

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