UCI Chem 1A Midterm 2

What are the general periodic trends of electronegativity?

Increases left to right across a period

decreases from top to bottom

What are the general periodic trends of atomic radii?

decreases from left to right

increases from top to bottom

What is effective nuclear charge?

net positive charge that is attracting a particular electron

What is paramagnetism?

electron configurations that result in unpaired electrons mean that the atom or ion will have a net magnetic field; has magnetic properties

What is diamagnetism?

electron configurations that result in all paired electrons mean that atom or ion will have no magnetic field; doesn't have magnetic properties

What is the electron configuration of Al^3+ and is it dia or para magnetic?

[He] 2s^2 2p^6

diamagnetic

What is the electron configuration of S^2- and is it dia or para magnetic?

[Ne] 3s^2 3p^6

diamagnetic

What is ionization energy?

the minimum energy needed to remove an electron from an atom or ion in the gas phase

Is Ionization energy endothermic or exothermic?

endothermic

Is first ionization energy larger than second ionization energy?

no

Does first ionization energy increase down a group?

no

Does first ionization energy increase across a period?

yes

What is electron affinity?

energy associated with the addition of an electron to the valence shell of an atom that is in the gas phase

Which direction does electron affinity become more negative?

left to right

Some characteristics of metals

conduct heat and electricity

form cations in solution

lose electrons in reactions(oxidized)

Some characteristics of nonmetals

Electrical and thermal insulators

form anions and polyatomic anions

gain electrons in reactions(reduced)

Does metallic character decrease left to right across a period?

yes

Does metallic character decrease down the column?

no, it increases down

Which element is more metallic? Sn or Te?

Sn

Electrons that are shared by atoms

Bonding pairs

electrons that are not shared by atoms but belong to a particular atom

lone pairs

two atoms share one pair of electrons

single covalent bond

two atoms share two pairs of electrons

double covalent bond

two atoms share three pairs of electrons

triple covalent bond

What is molecular mass?

mass of an individual molecule or formula unit; mass of one mole of that compound

What is the formula mass of glucose(C6H12O6)

180.16 amu

Calculate mass percent of Cl in Freon-112(C2Cl4F2)

69.58 %

What is empirical formula?

simplest whole-number ratio of the atoms of elements in a compound

A hydrogen compound was burned in air yielding 36g of water and 44g of carbon dioxide What is the empirical formula for the hydrocarbon?

CH4

What is molecular formula?

multiple of the empirical formula and is the actual formula of the compound

Empirical formula is C2H3O and its molar mass is 86.09 g/mol. Find its molecular formula.

C4H6O2

Equal sharing of electrons

Non-polar covalent bond

Unequal sharing of electrons

Polar covalent bond

No sharing of electrons in bond

Ionic Bond