Chapter 7

Question 1

What is the Pauli exclusion principle?

Answer 1

No more than two electrons can be assigned to the same orbital, and, if there are two electrons in the same orbital, they must have opposite spins. This leads to the general statement that no two electrons in an atom can have the same set of four quantum numbers (n, l, m_l, m_s)

Question 2

How we called the procedure by which electrons are assigned to orbitals.

Answer 2

the Aufbau principle

Question 3

What is the effective nuclear charge symbol?

Answer 3

Z*

Question 4

What is the electron configuration symbol of Group 1A-2A and He?

Answer 4

S

Question 5

What is the electron configuration symbol of Group 3A to 8A?

Answer 5

P

Question 6

What is the electron configuration symbol of transition metals?

Answer 6

d

Question 7

What is the electron configuration symbol of lanthanide and actinides?

Answer 7

f

Question 8

electron configurations…..see book p.259

Answer 8

p.259

Question 9

electron configuration and quantum numbers ….see book p.259

Answer 9

p.259

Question 10

electron configurations of the transition elements ….see book p.261

Answer 10

p.261

Question 11

In electron configuration how do we form a monatomic anion?

Answer 11

To form a monatomic anion, one or more electrons is added to the valence shell of a non-metal atom so that the electron configuration of the ion is the same as the electron configuration of the next noble gas in the periodic table.

Question 12

in electron configuration how do we form a monatomic cation?

Answer 12

To form a cation from a neutral atom, one or more of the valence electrons is removed.

Question 13

in electron configuration if we form a monatomic cation to which electron shell the electrons are removed?

Answer 13

Electrons are always removed first from the electron shell of highest n.

to see it:
http://dq1ouwfo9m6uw.cloudfront.net/datastreams/f-d%3Aa0a471281ace41a87589335961bf5ec1%2BEQUATION%2BEQUATION.1

Question 14

in electron configuration if we form a monatomic anion to which electron shell the electrons are added?

Answer 14

Electrons are always added first from the last electron shell.

to see it: http://wiki.chemprime.chemeddl.org/images/a/aa/Fluoride_ion.jpg

Question 15

In electron configuration if we form an cation of transition metal which electron will be lost?

Answer 15

All transition metals lose their ns electrons first, and the cations formed all have electron configurations of the general type noble gas cored^x

Its the contrary of the other element which are not transition metals
to see: http://www.chembook.co.uk/New%20Eqns/Ch18eq2.png

Question 16

configuration of transition metal ions ….see book p.265

Answer 16

p265

Question 17

What is the definition of diamagnetic?

Answer 17

Substances in which all electrons are paired (with the two electrons of each pair having opposite spins) experience a slight repulsion when subjected to a magnetic field

Question 18

What is the definition of paramagnetic?

Answer 18

Elements and compounds that have unpaired electrons are attracted to magnet.

Question 19

What the atomic size of an atom can determines?

Answer 19

size can determine the number of atoms that may surround and be bound to a central atom and can be a determining factor in the shape of a molecule

Question 20

What is the trend in the periodic table for atomic radii?

Answer 20

For the main group elements, atomic radii generally increase going down a group in the periodic table and decrease going across a period.

Question 21

What is the periodic trend in the atomic radii of transition metal atoms.

Answer 21

Going from left to right in a given period, the radii initially decrease

Question 22

What is the ionization energy?

Answer 22

Ionization energy (IE) is the energy required to remove an electron from an atom in the gas phase.

Question 23

Ionization energies always have __________(positive or negative) values

Answer 23

Ionization energies always have positive values.

Question 24

Does an electron close from the nucleus have a smaller or larger ionization energy?

Answer 24

An electron farther from the nucleus generally has a smaller ionization energy, and an electron closer to the nucleus has a larger ionization energy.

Question 25

For main group element what is the periodic trend of the first ionization energies?

Answer 25

For main group (s- and p-block) elements, first ionization energies generally increase across a period and decrease down a group

Question 26

What is the definition of electron attachment enthalpy ?

Answer 26

The electron attachment enthalpy, is defined as the enthalpy charge occurring when a gaseous atom adds and electron, forming a gaseous anion.

Question 27

What is the definition of electron affinity?

Answer 27

The electron affinity, EA, of an atom is closely related to electron attachment enthalpy. Electron affinity is equal in magnitude but opposite sign to the internal energy change associated with a gaseous atom adding an element.

Question 28

periodic trends

Compare 3 elements: C,O and Si

a) place them in order of increasing atomic radius
b) Which has the largest ionization energy?
c) which has the most negative electron attachment enthalpy, O or C?

Example 7.5: Chemistry and chemical reactivity, 9th edition student book.

Answer 28

a) atomic radii decreases on moving across a period, so oxygen has a smaller radius than carbon. However, the radius increases on moving down a periodic group. Because C and Si are in the same group, silicon must be larger than carbon.
O, Si, C

b) Ionization energies generally increase across a period and decreases down a group. Thus, the trend in ionization energies is Si (787 kJ/mol) , C (1086 kJ/mol), O (1314 kJ/mol)
O has the larges ionization energy

c) values generally become less negative down a group (except for the second period elements) and more negative across a period. Therefore, O (= - 141.0 kJ/mol) has a more negative electron enthalpy than C (= -121.9 kJ/mol)

Question 29

What is the trend on ion sizes?

Answer 29

The trend in the sizes of ions down a periodic group is the same as that for neutral atoms: positive and negative ions increase in size when descending the group.

Question 30

When an electron is removed from an atom to form a cation does the size of the atom stays the same, expand or shrink?

Answer 30

When an electron is removed from an atom to form a cation, the size shrinks considerably.

Question 31

Does the radius of an atom is the same size as the radius of the cation?

Answer 31

The radius of a cation is always smaller than that of the atom from which it is derived.

Question 32

Does the radius of an atom is the same size as the radius of the anion?

Answer 32

Anions are always larger than the atoms from which they are derived