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CHEMISTRY, M1 EQ-Bank 30

Explain the trend in reactivity with water of the elements in Group 2 as you move down the group.   (2 marks)

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→ The reactivity of Group 2 elements with water increases as you move down the group due to decreasing ionization energies and increasing atomic radii.

→ Lower ionization energies and larger atomic radii make it easier for these metals to lose electrons and react with water, forming hydroxides and hydrogen gas. 

→ For instance, magnesium reacts slowly with hot water, while barium reacts vigorously even at room temperature, illustrating this trend.

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→ The reactivity of Group 2 elements with water increases as you move down the group due to decreasing ionization energies and increasing atomic radii.

→ Lower ionization energies and larger atomic radii make it easier for these metals to lose electrons and react with water, forming hydroxides and hydrogen gas. 

→ For instance, magnesium reacts slowly with hot water, while barium reacts vigorously even at room temperature, illustrating this trend.

CHEMISTRY, M1 2010 HSC 35d

Experimental evidence from emission line spectra of gaseous atoms has highlighted both the merits and the limitations of Bohr's atomic model. 

Discuss Bohr's atomic model with reference to this evidence.  (5 marks)

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→ The Bohr model of the atom describes the orbit of electrons around the nucleus at fixed radii and energy.

→ The emission line spectrum of hydrogen was seen to support the Bohr model as discrete lines were observed which could be assigned to electronic transitions between fixed energy levels.

→ However when the emission line spectrum for sodium was recorded there were more spectral lines than could be explained by the Bohr model. Line splitting or doublets were observed.

→ The line splitting or doublets result from electrons having differing angular momenta, residing in sub-shells, which was not considered in the Bohr model.

CHEMISTRY, M1 2013 HSC 6 MC

A representation of the Periodic Table is shown. The positions of six different elements, \(P, Q, R, S, T\) and \(U\) are given.
 

Which row of the following table shows the correct acid and base reactivities of the oxides of these elements?
 

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`A`

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→ Acidic Oxides: are often the oxides of non-metals and form acidic solutions

→ Basic Oxides: are usually formed by reacting oxygen with metals, they participate with acids in neutralisation rections

→ Neutral Oxides: react with neither acids or bases and do not lead to either acidic or basic solutions

→ Amphoteric Oxides: exhibit both acidic and basic properties, they can chemically react as either an acid or base

`=>A`