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Chemistry > The Atom > Flashcards

The Atom Flashcards

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1
Q

Heisenberg’s Uncertainty Principle

A

It’s impossible to measure both the velocity and position of an electron at the same time

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2
Q

An orbital

A

A region in space where there’s a high probability of finding an electron

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3
Q

Sublevel

A

A subdivision of a main energy level and consists of one or more orbitals of the same energy

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4
Q

Energy level

A

The fixed energy value an electron in an atom may have

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5
Q

Ground state of an atom

A

When the electrons in the atom occupy the lowest available energy levels

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6
Q

Excited state of an atom

A

When the electrons in the atom occupy higher energy levels than those available in the ground state

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7
Q

Dalton’s Atomic Theory

A

All matter is made up of tiny particles called atoms. Atoms are indivisible, can’t be broken down into smaller particles

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8
Q

Cathode rays

A
  1. Streams of electrons
  2. That travel in straight lines from the cathode to the anode
  3. Are deflected by electric/magnetic fields
  4. Have enough energy to move a paddle wheel
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9
Q

Diffusion?

A

The spreading of gases

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10
Q

What did Greek philosophers propose about the atom?

A

Matter is composed of small particles, called atoms

Atoms are indivisible

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11
Q

How did Crookes discover cathode rays?

A

He passed an electric current through air at a low pressure in a vacuum tube
He showed the rays were coming from the cathode (negative electrode)
The cathode rays cast a shadow of a cross at the other end

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12
Q

Cathode rays causes glass..?

A

To glow when they strike it

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13
Q

How did Crookes investigate the properties of cathode rays?

A

Paddle wheel experiment, he put a paddle wheel in front of a cathode
when the current was switched on the wheel spun
Conclusion: the wheel was being struck by particles coming from the cathode

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14
Q

Alpha particles

A

Groups of 2 protons+ 2 neutrons stuck together

Positively charged

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15
Q

Describe the plum pudding model proposed by JJ Thomson

A

The atom is like a sphere of positive charge with electrons embedded in the sphere at random

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16
Q

Pros and cons of JJ Thomson’s Plum pudding model?

A

Pro: explains why atoms are neutral
Con: no experimental evidence

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17
Q

Why are Relative Atomic masses rarely whole numbers?

A

They’re an average of all an element’s naturally occurring isotopes

18
Q

How can you detect the presence of cathode rays in a vacuum tube?

A

The paddle wheel spins (tiny particles strike it)

Glass glows at the other end

19
Q

Who discovered the electron?

A

JJ Thomson

20
Q

3 observations made by Rutherford when he bombarded gold foil with alpha particles…

A
  1. some reflected back on their own paths
  2. Some deflected at large angles
  3. Most didn’t deflect at all
21
Q

How did Rutherford prove that alpha particles are small and dense?

A

Only a small amount of alpha particles were deflected, because only a small amount came into contact with the (+) charged nucleus

22
Q

Mass number

A

The sum of protons+neutrons in the nucleus of an atom

23
Q

Relative Atomic Mass

A

The average of the mass numbers of all the naturally occurring isotopes of an element, taking their abundances into account and expressed on a scale where the atoms of the carbon-12 isotope have a mass number of 12 units

24
Q

Heterogenous catalysis

A

Catalysis where the reactant and the catalyst are in different stages, there’s a boundary between them

25
Q

Modern structure of the atom

A

Protons and neutrons together in the nucleus

Electrons in an “electron cloud” around the nucleus at any point on the orbital

26
Q

Radioactivity

A

The spontaneous breaking up of unstable nuclei with the emission of 1+ types of radiation

27
Q

3 types of radiation?

A

Alpha particles
Beta particles
Gamma radiation

28
Q

Radioisotope

A

A radioactive isotope

29
Q

2 assumptions of Dalton’s atomic theory

A

All matter is made up of atoms (tiny particles)

Atoms are indivisible

30
Q

Who measured the charge on the electron

A

Milikan (oil drop experiment)

31
Q

Who proved that electrons are in an electron cloud surrounding a small dense nucleus?

A

Rutherford

32
Q

Chat change occurs in the nucleus when it undergoes beta emission?

A

A neutron changes to a proton and an electron

33
Q

Heisenberg’s uncertainty principle

A

It’s impossible to measure bathe the velocity and position of an electron at the same time

34
Q

How did JJ Thomson discover the electron?

A

He obtained a narrow beam of cathode rays by passing them through a small hole in an anode
The beam passes through 2 metal plates (opposite charges)
The beam was attracted to the (+) charged plate, the spot on the end of the glass was near the top

35
Q

Milikan’s oil drop experiment?

A

Sprayed oil drops between 2 metal plates (opposite charges)
Used X-rays to ionise the air between the plates
Oil drops picked up electrons (-)
Oil drops attracted upwards (+)
Milikan adjusted until drops were stationary, so he could calculate the charge on the electron

36
Q

Purpose of Milikan’s oil drop experiment?

A

To find the charge on the electron

37
Q

Who discovered the nucleus and how?

A

Rutherford
He bombarded golf foil with alpha particles
Some reflected, some deflected at large angles, some weren’t deflected at all

Conclusion: most of the atom is empty space

38
Q

Who discovered the proton?

A

Rutherford

Positive particles in the nucleus

39
Q

Who discovered the neutron?

A

Chadwick

40
Q

Who came up it’s the modern atom structure/ electron cloud?

A

Rutherford

41
Q

Scientific name for materials?

A

Matter

Chemistry (12 decks)

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