- Combination of different types of atoms - Pure substances which consists of two or more elements chemically combined

Atomic Structure Flashcards by KJ Hall

Define chemistry:

Scientific discipline involved with elements and compounds composed of atoms, molecules and ions: their composition, structure, properties, behaviour and the changes they undergo during a reaction with other substances

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Define element:

Simplest substances and are made up from simple particles

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Define molecules:

More than one atom bonded together to either the same or different atoms

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Define compound:

Combination of different types of atoms

- Pure substances which consists of two or more elements chemically combined

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Define atom:

Smallest parts of an element that can exist chemically

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Are atoms the smallest particles?

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What is an atom composed of?

Neutrons
Protons
Electrons

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When looking a periodic table what is above the chemical symbol?

Atomic number

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When looking a periodic table what is bellow the chemical symbol?

Relative atomic mass

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What is a nucleus of an atom made of?

Protons and neutrons

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What is the symbol for a neutron?

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What is the mass (kg) of a neutron?

1.675 x10^-27

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What is the charge of a neutron?

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What is the symbol for a proton?

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What is the symbol for an electron?

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What is the mass (kg) of a proton?

1.673 x 10^-27

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What is the mass (kg) of a electron?

9.109 x 10^-31

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What is the charge of a electron?

-1

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What is the charge of a proton?

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Define atomic number:

Number of protons in nucleus

- Each element has its own atomic number

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Define relative atomic mass:

-Sum of the number of protons and the neutrons in the nucleus of an atom

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Define isotops:

Atoms of the same element with different numbers of neutrons

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How can we see atoms?

Transmission Electron Microscopy (TEM)

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How are atoms neutral?

Protons and electrons cancel out the charge

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What is quantum?

Fixed or discrete amount of something

What does the absorption of an electron cause the electron to do?

Jump to an excited state

How do you remove the excited state of an electron?

Removing the radiation - it will drop back to to ground state and unit

What do emission spectrums show?

An electron absorbing a specific, fixed quantity of energy

What is Bohr's model of the H atom?

-Bohr orbits are quantised = specific absorption of energy for each transmission = r =kn^2

What is weird about electrons?

Demonstrate wave particle duality

What did Schrodinger propose?

That properties of waves could be used to explain the behaviour of electrons in atoms

What is an electron in a particular orbit described as?

Wavefunction

What is a wavefunction?

series of mathematical equations that model the distribution of electrons in an atom

What doe the quantum model show about the nucleus?

It is surrounded by clouds of electrons

What are regions of space referring to in the quantum model?

Electron or atomic orbitals

What does cloud of electrons equal to?

Cloud of probability

What is the atomic orbital theory?

Electrons in atoms are arranged in successive principle energy levels or shells

How many electrons can be held in the first shell?

2 electrons

How many electrons can be held in the second shell?

8 electrons

How many electrons can be held in the third shell?

18 electrons

What model did Dalton come up with?

Solid sphere model

What were the positives about the solid sphere model?

Recognised atoms of a particular element differ form other elements

What were the negative about the solid sphere model?

Atoms are indivisible - they are composed from subatomic particles

What model did Thomson come up with?

Plum pudding model

What are the positives about the plum pudding model?

Recognised electrons as components of atoms

What are the negatives about the plum pudding model?

No nucleus; didn't explain later experimental observations

What model did Rutherford propose?

Nuclear model

What are the positives of the nuclear model?

Realised positive charge was localised in the nucleus of the atom

What are the negatives of the nuclear model?

Did not explain why electrons remain in orbit around the nucleus

What model did Bohr propose?

Planetary model

What are the positives of the planetary model?

Proposed stable electron orbits; explained the emission spectra of some elements

What are the negatives of the planetary model?

Moving electrons should emit energy and collapse into the nucleus model did not work well for heavier atoms

What model did Schrodinger propose?

Quantum model

What are the positives of the quantum model?

- Shows electrons don't move around the nucleus in orbit, but clouds where they position is uncertain - Widely accepted as the most accurate model of the atom

What is an atomic orbital?

Region around an atom where there is a high probability of finding an electron

Finish the sentence: | Higher the principle quantum number...

the further the electron density spreads away from nucleus

Describe the s-orbitals:

- Spherical - Symmetrical about all three axis - Found at all principle quantum numbers - Hold max. of 2 electrons

Describe the p-orbitals:

- Three p orbitals - Identical in shape - Point in different directions, one along each axis - Found at principle quantum number n=2 and above - Each orbital holds a max. of 2 electrons

Describe the d-orbitals:

- Five d-orbitals - Complicated shape - Found at principle quantum number n=3 and above - Each orbital holds a max. of 2 electrons

Describe the f-orbitals:

- Seven f-orbitals - Very complicated shape - Found at principle quantum number n=4 and above - Each orbital holds a max. of 2 electrons

How many electrons in n=1?

What are the atomic orbitals in n=2?

How many electrons in n=2?

What are the atomic orbitals in n=2?

2s 2px 2py 2pz

How many electrons in n=3?

What are the atomic orbitals in n=3?

3s 3px 3py 3pz | 3dxy 3dxz 3dyz 3dx2-y2 3dz2

How many electrons in n=4?

What are the atomic orbitals in n=4?

4s 4px 4py 4pz 4dxy 4dxz 4dyz 4dx2-y2 4dz2 Seven 4f orbitals

What are five 3d orbitals are?

Degenerate

What is the electronic configuration?

Arrangement of electrons within an atom

What is the Pauli exclusion principle?

Each individual orbital contains a max. of two electrons with opposite spins

Why do two electrons in an orbital have opposite spins?

To mimosa repulsion between two electrons

Finish the sentence: | Electrons occupy the ...

lowest energy vacant orbitals

What is the Hund's rule of max. multiplicity?

Electrons fill a set of degenerate energy orbitals by keeping their spins parallel

What is the Aufbau principle?

To populate orbitals for a given atom, start at the lowest energy orbital and work upwards

What does an atom in the ground state?

A configuration with the greatest number of unpaired electrons