chem chapter 6 quiz Flashcards
all atoms need 8 electrons, except…
hydrogen needs 2, boron needs 6, beryllium needs 4
what element is usually the central atom in lewis structure
least electronegative
the number of available electrons is equal to the _____________
number of valence electrons of the atom
shared electrons=
N-A (always even)
number of bonds=
S/2
H is never involved in a multiple bond
___,____ and ___ often form double and triple bonds
C, N, O
total number of electrons should equal the ______ number
A
what is the metallic trend
increases up to down, right to left
what is the atomic radii trend
why
increases up to down(valence electron is occupying higher energy level/n value increases making radius larger), increases right to left (number of protons increases (nuclear charge) pulling the electrons in tighter making the radius smaller
the differences in electronegativities is the classifier of bonds, what are the ranges for each
polar covalent 1.7>or equal to x > or equal to .5
pure covalent x<.5
ionic x>1.7
isoelectronic means?
same number of electrons
what is the atomic radii
distance from the center of the nucleus to the “edge” of the electron cloud
usually measured in picometers or angstroms (1x10^-10m)
must be in gas form
center of nucleus to center of nucleus divided by 2
what is the atomic radii trend for cations?
anions?
cations: increases up to down, right to left
anions: increases up to down, left to right
when hydrogen becomes an ion, it is just an ____
electron
______ do not have ionic radii because they do not form ions
noble gases
what is shielding effect
inner electrons shield valence electrons from positive charge of the nucleus (protons) (concert analogy)
what is the ionization energy trend
increases down to up, left to right
ionization energy is always _____ meaning energy is added to the atom to remove the electron
endothermic
how are ionization energy and atomic radius related
inversely proportional
what is ionization energy
the energy required to move an electron from an atom is ionization energy
the larger the atom is, the (harder/easier) it is for electrons to be removed
easier
why does ionization energy increase left to right? down to up?
because atoms towards the right do not want to gain electrons, they want to lose
because the electrons are held in lower-energy orbitals, closer to the nucleus and therefore are more tightly bound (harder to remove).
what is the electron affinity trend
increases down to up, left to right
what is electron affinity
a measure of the energy change when an electron is added to a neutral atom to form a negative ion
what is electron affinity opposite of
ionization energy
why does electron affinity increase down to up, left to right
because the electrons added to energy levels become closer to the nucleus, thus a stronger attraction between the nucleus and its electrons
what is the electronegativity trend
increases down to up, left to right
what is electronegativity
holding onto its own electrons and taking other ones
why does electronegativity increase down to up and left to right
This occurs due to a greater charge on the nucleus, causing the electron bonding pairs to be very attracted to atoms placed further right on the periodic table
what is the difference between electron affinity and ionization energy
electron affinity is a measure of the energy change when an electron is added while ionization energy is the energy required to remove an electron
why does fluorine have a higher ionization energy than iodine?
it has less electrons-lesser shielding/greater attraction between the electrons and the nucleus
why do elements in the same family generally have similar properties
they have the same amount of valence electrons
