Chapter 5 Review Flashcards
What were Stanislao Cannizzaro’s contributions to the development of the periodic table?
- presented a convincing method for accurately measuring the relative masses of atoms, which:
- enabled chemists to agree on standard values for atomic mass
- initiated a search for relationships between different properties of the elements, like atomic mass.
What were Dimitri Mendeleev’s contributions to the development of the periodic table?
- created the very first periodic table
- elements of similar properties were grouped together
- his procedure left blank spaces for elements that had not yet been found
- predicted the properties of three blank space elements
- when those three elements were discovered
- their properties were found to be strikingly similar to Mendeleev’s predictions
- many chemists accepted his periodic table
- Mendeleev was credited as the discoverer of the Periodic Table
What were Henry Moseley’s contributions to the development of the periodic table?
- was examining the spectra of 38 different metals, when he discovered a previously unrecognized pattern
- he called it the periodic law, which was partially proven correct by its consistency with Mendeleev’s ordering of the periodic table
State the periodic law
“The physical and chemical properties of the elements are periodic functions of their atomic number.” This means that chemical and physical properties will reoccur periodically when arranged in an order based on their increasing atomic weight.
How is the periodic law demonstrated within the groups of the periodic table?
the elements in the periodic table are arranged based on their increasing atomic numbers so that elements with similar properties end up in the same group
a. how do the electron configurations within the same group of elements compare?
b. why are the noble gases relatively unreactive
a. they all end with the same amount of electrons in the same sublevel
b. elements become unstable when they are trying to obtain a full set of valence electrons (8), so noble gases are relatively unreactive, because they don’t need to unstablize themselves for more electrons, they already have a full set
what determines the length of each period in the periodic table
the number of electrons that an occupy the sublevels being filled in the period
a. what is meant by atomic radius?
b. what trend is observed among the atomic radii of main-group elements down a period (explain)
a. one-half the distance between the nuclei of identical atoms that are bonded together
b. decrease
what trend is observed among the atomic radii of main-group elements down a group (explain)
generally increase down a group, because electrons are farther away from the nucleus
a. ion
b. ionization
c. first ionization energy
d. second ionization energy
a. A charged atom or a charged group of bonded atoms
b. any process that results in the formation of an ion
c. energy required to remove one electron from a neutral atom
d. energy required to remove an electron from a 1+ ion
a. how do the first ionization energies of main-group elements vary across a period and down a group?
b. Explain the basis for each trend
a. They increase across a period and decrease down a group
b. Across a period, the increasing nuclear charge attracts electrons in the same energy level more strongly and makes them more difficult to remove. Down a group, electrons are farther from the nucleus so their easier to remove
a. what is electron affinity?
b. what signs are associated with electron affinity values, and what is the significance of each sign?
a. The energy taken in or given off when an electron is added to an atom
b. either negative (energy is given off) or positive (energy is taken in)
a. distinguish between a cation and an anion
b. how does the size of each compare with the size of the neutral aton from which it is formed?
a. a cation is a positive ion, an anion is a negative ion
b. cation is smaller, anion is bigger
a. what are valence electrons?
b. where are such electrons located?
a. valence electrons are electrons that can be gained, lost, or shared in chemical compounds
b. outermost energy level
for each of the following groups, indicate whether electrons are more likely to be lost or gained in compound formation and give the number of such electrons typically involved
a. group 1
b. group 2
c. group 13
d. group 16
e. group 17
f. group 18
a. lose 1
b. lose 2
c. lose 3
d. gain 2
e. gain 1
f. doesn’t lose or gain
a. what is electronegativity?
b. why is fluorine special in terms of electronegativity?
a. how attractive an atom is to electrons of other atoms
b. fluorine was randomly assigned the value of four and that value is used to to calculate the values of otehr elements
identify the most- and the least- electronegative groups of elements in the periodic table
group 17 is the most, group 1 is the least
Of cesium (Cs), hafnium (Hf), and gold (Au), which element has the smallest atomic radius? Explain answer in terms of trends in the periodic table.
Gold, because the farther right in the period, the more attracted electrons are to the nucleus
a. distinguish between the first, second, and third ionization energies of an atom
b. how do the values of successive ionization energies compare?
c. why does this occur?
a. the first takes aways the first electron, then the second will take away a second electron, and the third will take aways a third electron
b. each value is plus one
c. a greater positive charge has to be used to remove each successive electron
Without looking at the electron affinity table, arrange the following elements in order of decreasing electron affinities: C, O, Li, Na, Rb, and F
F > O > C > Li > Na > Rb
a. Without looking at the ionization energy table, arrange the following elements in order of decreasing first ioniation energies: Li, O, C, K, Ne, F
b. which of the elements listed in (a) would you expect to have the highest second ionization energy? why?
a. Ne > F > O > C > Li > K
b. Li - For both Li and K, the second electron must come from a completely filled noble gas electron configuration. Li is the highest though, because Li+’s radius is smaller than the radius of K+
a. which of the following cations is least likely to form: Sr^2+, Al^3+, or K^2+?
b. which of the following anions is least likely to form: I^-, Cl^-, O^2-?
a. K^2+
b. O^2-
Which element is the most electronegative among C, N, O, Br, and S? Which group does it belong to?
O; group 16
The two ions K^+ and Ca^2+ each have 18 electrons surrounding the nucleus. Which could you expect to have the smaller nucleus? Why?
Ca2+ because it has 20 protons to pull the nucleus in where K+ only has 19 protons.
