Chem test sat 1 Flashcards
Why is each element’s absorption and emission spectra unique?
Each element contains differing numbers of electrons, therefore all have different energy levels.
Explain how absoprbtion spectra are produced, and how do they work?
Absorption spectra occurs when energy passes into an atom, and the atoms jump up energy levels, this state is unstable though, so they jump back down an energy level and emit a photon, (spectra).
Is electrons in the inner shell our outer shell have higher energy levels.
Outer Shells
Size of the atom across period?
Decreases, more valance electrons, tighter the atom is.
Tendency to gain electrons across a period?
Increases, period 7 is most likely to gain electrons, rather than loose them.
Metallic character across a period?
Decreases across the period.
Number of valence electrons across a period?
increases
Numbers of protons across a period?
Increases across the period.
What is a period?
Across, rows
What is a group?
Down, columns
Define atomic radius.
Atomic radius is the measurement from the centre of the nucleus to the outermost electron.
Define electronegativity? What are the trends for electronegativity?
Electronegativity is the ability of an atom to attract electrons to itself. Fluorine is the most electronegative, decreases down a group, increases across a period.
Define Homogenous mixture.
Homogenous mixtures are those in which the components are mixed uniformly such that all parts have the same chemical composition. Seawater is an example of this, all parts containing the same composition of salts and water. Or air
Define heterogenous mixture.
Heterogenus mixtures are those where the components are not mixed uniformly throughout. For example ceral and milk. Soil or blood
Are molecules comprised of the same element polar or non-polar?
Always non-polar
