Test
Physical atomic structure chapter
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Preguntas del test (16)
1The order of magnitude of the diameter of an atom is 10^[blank_start]-10[blank_end] metres.
- A-10
2The actual diameter of an atom ranges from [blank_start]0.1[blank_end]nm to [blank_start]0.5[blank_end]nm
- A0.1
- B0.5
3[blank_start]Atomic force[blank_end] microscopes and [blank_start]scanning tunnelling[blank_end] microscopes can be used to generate images of individual atoms.
- AAtomic force
- Bscanning tunnelling
4You can use an AFM image or a STM image to estimate the diameter of an atom by [blank_start]counting[blank_end] the number of atoms up the side of an image and dividing the true height of the image by it.
- Acounting
5Atomic force microscopes work by [blank_start]dragging[blank_end] a fine needle tip made of [blank_start]silicon nitride[blank_end] across the surface of a specimen. Successive atoms either [blank_start]attract[blank_end] or [blank_start]repel[blank_end] the tip, and the actuator works to keep the [blank_start]force[blank_end] between the needle and the surface constant. This is done using a laser sensor- a laser is shone onto a [blank_start]mirror[blank_end] atop the needle and reflects into a sensor.
- Adragging
- Bsilicon nitride
- Cattract
- Drepel
- Eforce
- Fmirror
6Scanning tunnelling microscopes work by [blank_start]dragging[blank_end] a fine needle tip across the surface of a specimen. A [blank_start]potential difference[blank_end] is applied to the needle tip which causes electrons to tunnel from the specimen surface to the needle tip, and hence a [blank_start]current[blank_end] flows. The actuator works to keep this current [blank_start]constant[blank_end].
- Adragging
- Bpotential difference
- Ccurrent
- Dconstant
7Rayleigh's oil drop experiment can only be used to generate an [blank_start]order of magnitude[blank_end] estimate for the diameter of an atom because of the huge [blank_start]uncertainty[blank_end] in the final value, and because we [blank_start]assume[blank_end] the oil spreads out perfectly across the water surface.
- Aorder of magnitude
- Buncertainty
- Cassume
8In the oil drop experiment, first we coat a tray of water in [blank_start]lycopodium[blank_end] powder. Then we take a loop of copper wire and use it to pick up an oil [blank_start]droplet[blank_end]. We measure the diameter of the oil droplet either directly or by taking a photo. Now we dip the metal loop in the water so an oil slick propagates. We need to measure the diameter of this slick before it [blank_start]contracts[blank_end].
- Alycopodium
- Bdroplet
- Ccontracts
9Derive the equation for the diameter of an atom when using the oil drop experiment. Type done when done. [blank_start]done[blank_end]
- Adone
10The oil drop experiment gives a [blank_start]maximum[blank_end] estimate for the diameter of an atom.
- Amaximum
- Bminimum
11The simplest model of the atom is called the [blank_start]Rutherford[blank_end] model
- ARutherford
12In the Rutherford model, there is a [blank_start]dense[blank_end] nucleus at the centre of the atom made up of [blank_start]protons[blank_end] and [blank_start]neutrons[blank_end], and electrons move around the nucleus in the negative electron [blank_start]cloud[blank_end]. The nucleus makes up the majority of the [blank_start]mass[blank_end] of the atom but a negligible amount of the [blank_start]volume[blank_end].
- Adense
- Bprotons
- Cneutrons
- Dcloud
- Emass
- Fvolume
13The Rutherford model was derived using experimental evidence from the [blank_start]gold[blank_end] foil experiment.
- Agold
14In the gold foil experiment, a [blank_start]thin[blank_end] piece of gold foil was bombarded with [blank_start]alpha[blank_end] particles. It was found that the majority of the particles passed through unaffected but a tiny fraction were [blank_start]deflected[blank_end] through a significant [blank_start]angle[blank_end]. It was concluded firstly that there were well-separated [blank_start]massive[blank_end] particles in the atomic structure and secondly that these particles were [blank_start]positively[blank_end] charged.
- Athin
- Balpha
- Cangle
- Ddeflected
- Emassive
- Fpositively
15The diameter of a nucleus is around [blank_start]100[blank_end]fm. 1fm is equal to 10^[blank_start]-15[blank_end] metres
- A100
- B-15
16The problems with the Rutherford model were: If the electrons were [blank_start]stationary[blank_end] then they would just [blank_start]fall[blank_end] into the nucleus; and if they revolved around the nucleus then they would constantly be [blank_start]accelerating[blank_end] since their velocity [blank_start]vector[blank_end] would constantly be changing direction towards the centre of the orbit so they would constantly [blank_start]radiate[blank_end] energy, lose kinetic energy and spiral into the nucleus.
- Astationary
- Bfall
- Caccelerating
- Dvector
- Eradiate
Información
- Descripción
- Test sobre Physical atomic structure chapter, creado por Dylan Reilly el 29/08/2021.
- Autor
- Dylan Reilly
- Idioma
- English
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