Chemistry Test 1 ATAR year 11

What did Dalton propose in 1803 regarding atomic theory?

Atoms are solid, indivisible spheres.

Who discovered the electron in 1897?

J.J. Thomson.

What is the significance of Rutherford's gold foil experiment?

It led to the nuclear model of the atom.

In what model did Bohr propose electrons orbit the nucleus?

Specific energy levels.

What particle did Chadwick discover?

The neutron.

What is the name of the outermost shell in an atom?

The valence shell.

What does the atomic number represent?

The number of protons in an atom.

How does atomic radius change across a period in the periodic table?

It generally decreases from left to right.

What is ionization energy?

The energy required to remove an electron from an atom.

How does electronegativity change down a group in the periodic table?

It generally decreases.

What do flame tests and AAS measure in atoms?

The emission or absorption of light produced as electrons transition between energy levels.

What are isotopes?

Atoms of the same element with the same number of protons but different numbers of neutrons.

What does mass spectrometry analyze?

The isotopic composition of elements.

What role does a fractionating column play in fractional distillation?

It provides a larger surface area for condensation and vaporization to separate liquid mixtures.

What separates substances based on their density?

Centrifugation.

What is the principle behind chromatography?

It separates substances based on their affinities for a stationary phase and a mobile phase.

Who proposed the concept of 'atomos' around 400 BC?

Leucippus and Democritus.

What does the relative atomic mass reflect?

The weighted average of the masses of an element's isotopes based on their abundances.

What did Erwin Schrödinger develop in 1926?

The quantum mechanical model of the atom.

What do atoms tend to achieve in their valence shell for chemical stability?

A stable configuration, often with eight electrons (octet rule).

Who proposed the 'plum pudding' model of the atom?

J.J. Thomson.

What happens to electrons when atoms are heated in flame tests?

Electrons jump to higher energy levels and release energy as they return to ground state.

What defines an element in the periodic table?

The number of protons.

What is the main characteristic of the nuclear model of the atom?

A small, dense, positively charged nucleus surrounded by mostly empty space.

What did Niels Bohr introduce in his atomic model?

Electrons orbiting the nucleus in specific energy levels.

What occurs during the ionization step of mass spectrometry?

Atoms or molecules lose electrons and become positively charged ions.

What determines the separation of components in chromatography?

Different affinities for the stationary and mobile phases.

How does atomic radius change down a group in the periodic table?

It generally increases.

What technique separates liquids based on their boiling points?

Distillation.

What is the first modern atomic theory developed by Dalton based on?

Solid, indivisible spheres.

What describes electrons in Schrödinger's quantum mechanical model?

Wave-like particles in orbitals.

What is the relationship between protons and electrons in a neutral atom?

They are equal in number.

Why is the outermost shell important for chemical bonding?

It determines how atoms interact with each other.

What is the purpose of the detector in mass spectrometry?

To record the number of ions of each mass-to-charge ratio.

What does increasing nuclear charge do to ionization energy across a period?

It generally increases the ionization energy.

What does the term 'mass-to-charge ratio (m/z)' refer to in mass spectrometry?

The value used to deflect ions in a magnetic field based on their mass and charge.

What principle explains the ability of an atom to attract electrons in a chemical bond?

Electronegativity.

How are elements with similar properties organized in the periodic table?

They are placed in the same group (vertical column).

What analytical technique involves spinning a mixture at high speeds?

Centrifugation.

What occurs as electrons transition from higher energy levels back to their ground state?

They release energy in the form of light.

What do atoms achieve by gaining, losing, or sharing electrons?

A stable valence shell configuration.

What does increasing atomic number in the periodic table indicate?

Increasing number of protons in the elements.

What happens to ionization energy down a group?

It generally decreases.

What type of energy levels do electrons occupy according to Bohr's model?

Specific energy levels or shells.

What distinguishes isotopes of an element?

Their different numbers of neutrons.

What technique is used for identifying elements based on light absorption?

Atomic Absorption Spectroscopy (AAS).

In the periodic table, what trend is observed regarding electronegativity across a period?

It generally increases.

What historical atomic model did Thomson develop after discovering the electron?

The plum pudding model.