Topic 3: Periodicity Flashcards
How is the periodic table arranged? Four major components.
Ptable is arranged by last orbital (spdf). Elements are arranged by increasing atomic number. Groups are columns with the same number of valence e-, and periods are rows with the same number of energy levels
From left to right, what are the different types of elements?
Alkali metals (not hydrogen), alkaline earth metals, transition metals (lanthanoids and actinoids at bottom left of trans. metals), other metals, other non metals, halogens, noble gases.
What are the trends for atomic/ionic radius, melting point, ionization energy, electonegativity, and reactivity for alkali metals?
Radius increases down the group, as does reactivity bc it is easier to lose e-. IE, melting point, electronegativity decrease down the group. Melting point decreases because larger atoms mean weaker metallic bonds.
What are the trends for atomic/ionic radius, melting point, ionization energy, electonegativity, and reactivity for halogens?
Same as alkali except melting point and reactivity: Radius increases down the group, IE, electronegativity decrease down the group. Melting point increases down the group because of increased Van Der Waal forces. Reactivity decreases down the group because it is harder for larger halogen atoms to gain e-.
What are some properties of period 3 metals?
Na, Mg, Al: shiny, solid at room temp, conductive, ductile/malleable, reducing agents, form cations, oxides and hydroxides act like bases to neutralize acids (except Al2O3, which is amphoteric)
What are some properties of period 3 nonmetals?
P, S, Cl, Ar: solids, liquids, gases, usually oxidants, form anions. Oxides tend to be acidic.
All period 3 oxides will react to form an ___or___ solution.
All period 3 oxides will react to form an acidic or alkali (basic) solution
What is periodicity?
repeating trends/patterns of physical and chemical properties in elements
What is atomic/ionic radius?
Distance from nucleus of atom/ion to outermost e-.
What is the trend for atomic/ionic radius?
Increases down a group as energy levels increase by 1 each period. Decreases across a period as protons are added, increasing electrostatic attraction between nucleus and e-.
What is first ionization energy?
Energy required to remove one mole of e- from one mole of gaseous atoms, or to remove 1 e- from an atom to turn it into an ion.
X(g)—> X^ +1 + e-
What is the trend for ionization energy?
Increases across a period as more protons=stronger attraction; harder to remove e-. Decreases down a group as more energy levels mean less attraction between nucleus and e-.
What is electron affinity?
Energy released when one mole of e- is added to one mole of gaseous atoms. X (g) + e- —> X^ - 1 (g)
What is the trend for electron affinity?
Generally, metals have low EA and nonmetals have high EA. Greater distances between nucleus and valence electrons means weaker attraction, so less energy released when an e- is added to an atom.
What is electronegativity?
The measure of the attraction an atom has for a shared pair of e- in a covalent bond
