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Flashcards in Chapter 12 Deck (36):
1

two types of bonds

ionic and covalent

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ionic bond

an electrostatic force between oppositely charged particles or ions - involves the transfer (loss and gain) of electrons

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ionic compounds

composed of metals and nonmetals

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covalent bond

formed by the sharing of electrons between two atoms - half filled orbitals overlap

5

covalent compounds

composed of two or more nonmetals - called covalent or molecular

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non polar covalent bond

results from the equal sharing of electron pairs

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polar covalent bonds

results from the unequal sharing of electron pairs

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electronegativity (electron affinity)

a measure of an atoms ability to attract electrons to itself - increases across a period and decreases down a group

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what determines the type of bond

the difference between electronegativities of the atoms - the greater the difference in electronegativity the more polar the bond

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electron configuration of ions

group a or main group metals form ions by losing enough electrons to achieve the electron configuration of the previous noble gas - nonmetals form ions by gaining electrons to achieve the electron configuration of the next noble gas

11

dot diagrams

show the symbol of the element with dots representing its valence electrons - dot diagrams can be used to show how ionic compounds are formed

12

atoms and ion sizes

cations are always smaller than the parent atom because when valence electrons are lost the remaining electrons are attracted closer to the nucleus, valence electrons are lost and there is now fewer levels - anions are larger than the parent atom because gaining electrons lessens the attraction between the electrons and the nucleus which creates a larger size

13

polyatomic ions

charged particles composes of 2 or more atoms, but the individual atoms are held together by covalent bonds

14

lewis structure

used to show how the atoms in a covalent bond or molecular compound are arranged

15

VSEPR

valence shell electron pair repulsion - the electron pairs (bonding and non bonding) around the central atom assume positions as far from one another as possible to minimize repulsion

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shape of a molecule

determined by the number of bonds and unshared pairs of electrons around the central atom

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linear

2 bonds, no unshared pairs

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trigonal planar

3 bonds, 0 unshared pairs

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tetrahedral

4 bonds, no unshared pairs

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pyramidal

3 bonds, 1 unshared pair

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bent

2 bonds, 2 unshared pairs

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angular

2 bonds, 1 unshared pair

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molecular polarity

molecules are classified as polar or non polar

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polar molecules

have a separation of charge due to polar bonds - the unequal sharing of the electron pairs causes one end of the molecule to have a positive charge and the other end to have a negative charge

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non polar molecules

contains non polar bonds - the electron pair is shared equally and no separation of charge occurs

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exception to polar bonds

molecules that contain polar bonds but have complete symmetry are non polar - the symmetry causes the poles to cancel each other out

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exception to octet rule

atoms that have an empty d sublevel can have more than an octet of electrons around the central atom - by the promotion of electrons, atoms can end up with more than 4 half filled orbitals

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trigonal bipyramidal

5 bonds, 0 unshared pairs

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seesaw

4 bonds, 1 unshared pair

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t-shaped

3 bonds, 2 unshared pairs

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linear 2.0

2 bonds, 3 unshared pairs

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octahedral

6 bonds, 0 unshared pairs

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square pyramidal

5 bonds, 1 unshared pair

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square planar

4 bonds, 2 unshared pairs

35

resonance structures

molecules that can have more than one acceptable lewis structure - contains a double bond, 1 central atom, follows octet rule

36

bond

the force that holds atoms together in a compound