Electron Config and Periodicity Definitions and Formulas

Question 1

Electron Configuration

Answer 1

• Distribution of electrons among the various orbitals in the atom among the available subshells.
• Maximum capacities of subshells and priciple shells can be predicted using this formula: 2n²

Question 2

Orbital Diagrams

Answer 2

• a diagram to show how the orbitals of a subshell are occupied by electrons.
• Boxes or circles to represent orbitals within subshells and up or down arrows to represent electrons.
• Number of orbitals in a subshell in a given l is 2l + 1

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Question 3

Pauli Exclusion Principle

Answer 3

• No two electrons in an atom can have the same four quantum numbers
• An orbital can hold at most two electrons, and then only if the electrons have opposite spins.

Question 4

How do you use the Aufbau Principle?

Answer 4

• Building-up principle (Aufbau principle): scheme used to reproduce the electron configurations of the ground states of atoms by successively filling subshells with electrons in a specific order.
• Start with the atomic number of the element in question, build up to fill the orbital limits and suborbitals.
• we could use noble gas core abbreviated configuration to show part of the configuration that corresponds to the configuration of a noble gas. Ex: for Neon: [He]2s²2p⁶
• Most ground states are correct, except for Cr,Cu,Nb,Mo,Te,Ru,Pd,Ag,Ag,La,Ir,Pt,Au,Ac

Question 5

Write the electron configuration using the periodic table

Answer 5

• S-subshells contain main group 1 and 2 including the He element. (2 groups)
• P-subshells contain main group 3 - 8 (6 groups)
• D-Subshells contain the transitional elements. Row numbers start at (n-1)d (10 groups)
• F-Subshells contain the lanthanided and Actinides, row numbers start at 4 (14 groups, last group is for d-shell, atomic # 71 and 103).
• The value of n is obtained from the period number
• For Ga: on the periodic table you get 1s 2s2p 3s3p 4s3d4p rearranged is 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p¹

Question 6

Determine the configuration of an Atom using Period and Group Numbers

Answer 6

• If the atom is a main-group element, the valence configuration is ns^anp^b where n = period and a+b = group number.
• If the atom is a transition element, the valence configuration is (n-1)d^a-2n^s where n = period and a is the group number (except 8B, count 8,9,10 for successive columns, which then equals a)

Question 7

Hunds Rule

Answer 7

The lowest-energy arrangement of electrons in a subshell is obtained by putting electrons into seperate orbitals of the subshell with the same spin before pairing electrons.

Question 8

Paramagnetic substance

Answer 8

Substance that is weakly attracted by a magnetic field, and this attraction is generally the result of unpaired electrons.

Question 9

Diamagnetic Substance

Answer 9

Substance that is not attracted by a magnetic field or is very slightly repelled by such a field. this property generally means that the substance has only paired electrons.

Question 10

Ferromagnetism

Answer 10

Strong atrtraction of iron and other substances to a magnetic field because of unpaired electrons.

Question 11

Periodic Law

Answer 11

• When the elements are arranged by atomic number, their physical and chemical properties vary periodically
• These physical properties that have periodic trends are atomic radius, ionization energy and electron affinity.

Question 12

Atomic radius

Answer 12

• maximum in the radial distribution function of the outer shell of the atom.
• also called the covalent radius, is the value for that atom in a set of covalent radii of atoms A and B predicts the approximate A–B bond length.

Question 13

Atomic Radius Trends in the Perodic Table

Answer 13

1. Within each period (Horizontal Row)
   
   1. The atomic radius tends to decrease with the increasing atomic number.
   2. i.e. Largest is at the bottom of group 1A
2. Within each group (vertical Column)
   
   1. the atomic radius tends to increase with the period number.
   2. i.e. smallest is at the top of group 8A

Question 14

Effective nuclear charge

Answer 14

the positive charge that an electron experiences from the nucleus, equal to the nuclear charge but reduced by any shielding or screening from any intervening electron distribution.

Question 15

First Ionization Energy Trend

Answer 15

• Also known as First ionization potential
• The minimum amout of energy required to remove the most loosly bound electron from an isolated gadeous atom to form an ion with a +1 charge.
• There are irregularities in the the trend, but generally ionization energy increases across the period and decreases down a group. largest is at the top of group 8A

Question 16

Basic Oxide

Answer 16

Oxide that reacts with acids.

Question 17

Acidic Oxide

Answer 17

Oxide that reacts with bases

Question 18

Amphoteric Oxide

Answer 18

an oxide that has both basic and acidic properties.

Question 19

Electronic Affinity Trend

Answer 19

• Electron affinity is the energy change that occurs when an electron is added to an isolated gaseous atom to form an ion with a -1 charge.
• Elements with very negative affinities gain electrons easily to form negative anions.
• trend is not regular but tends to increase across the period and up a group. Largest is at the top of group 8A