Chemistry Test unit 3

Lanthanides

(4f) series have atomic numbers 57-71. These metals are shiny and reactive. Some are used as phosphors that glow when electrons hit them.

Actinides

(5f) series have atomic numbers 89-103. These metals are all radioactive. Many are man-made. Uranium is important in nuclear energy reactions.

What is the order of electron configuration?

Electrons fill up empty orbitals before sharing with other electrons

Define electronegativity

an atom's attraction for another atom's electrons ranges from 1 to 4

Henry Moseley

arranged elements by increasing atomic number

How was the periodic table arranged in the past?

based on physical properties

ionic bond

greater than 1.7 metal and nonmental

Define electron configuration

he distribution of electrons of an atom or molecule in atomic or molecular orbitals.

Lothar Meyer

he published his own table of the elements organized by increasing atomic mass--> same time as Mendeleev

valence electrons

Electrons on the outermost energy level of an atom those electrons found on the outside edge of the atom, farthest away from the nucleus.

When does the atomic radius decrease on the periodic table?

From left to right in rows on the periodic table

how many valence electrons can an atom have?

1 to 8

number of electrons for the first 4 energy levels

2,8, 18, 32

Pauli Exclusion Principle

A maximum of two electrons may occupy a single orbital, but only if the electrons have opposite spins.

Aufbau Principle

An electron occupies the lowest-energy orbital that can receive it. electrons occupy the orbitals of lowest energy first.

inversely proportional

Are ionization energy and atomic radius directly or inversely proportional?

What is e- shielding?

As more energy levels are added to atoms, the inner levels of electrons shield the outer electrons from the nucleus' attraction. The effective nuclear attraction for these outer electrons is less, and so the outer electrons are less tightly held. This makes it easier to remove some of these e- when bonding to other atoms.

What are metalloids?

Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Astatine

non polar covalent bond

Electronegativity is less than 0.5 electrons equally shared

Why are there exceptions to the electron configuration rules?

Exceptions to the Aufbau principle are based on the fact that a few atoms are more stable when their electrons fill or half-fill an electron shell or sub shell. According to the Aufbau principle, these electrons should always fill shells and subshells according to increasing energy levels. Elements such as copper and chromium are exceptions because their electrons fill and half-fill two subshells, with some electrons in the higher energy level shells.

Alkali metals

Group 1 These are soft metals whose outer electron shell has an s 1 configuration. These are the most active metals. tend to react quickly with air or water, producing a basic solution in water. lose the s 1 electron and become ions with a +1 positive charge. Notice that if this happens they have the the electron configuration of a noble gas.

alkaline earth metals

Group 2 Their outer electron shell has an s 2 configuration. are harder and less reactive than the Group 1 metals. lose the s 2 electron and become ions with a +2 positive charge. Notice that if this happens they have the electron configuration of a noble gas.

Chalcogens (oxygen family)

Group 6 They have an outer electron configuration of s 2 p 4 so they try to gain 2 electrons so they can have the electron configuration of a noble gas. If they do this they become ions with a -2 charge. Oxygen is the most reactive element of this group.

Halogens

Group 7 They form salts with the Group 1 metals. They are the most reactive nonmetals . Their outer electron shell is p 5 if they gain one electron they can have the electron configuration of a noble gas. If they do this they are ions with -1 charge.

Noble gases

Group 8 They have filled s and p sublevels in their highest energy level. Having these electron shells filled makes them very stable. They are not willing to gain, lose or share electrons, so they will not react with other elements. have the highest ionization energy, and they have zero electron affinity and electronegativity.

Main Block elements

Groups 13 through 18 The metals in this group are aluminum, gallium, indium, tin, thallium, lead, bismuth, & polonium. The metalloids in this group are boron, silicon, germanium, arsenic, antimony & tellurium. The nonmetals in this group are hydrogen, oxygen, nitrogen, carbon, phosphorus, sulfur, selenium, fluorine, chlorine, bromine, iodine, and the noble gases.

s orbital filled

Groups 1A and 2A

Transition elements

Groups 3 through 12 are harder and less reactive than Group 1 & 2 metals. Because the outer shells of these elements are filling the d-orbital, they are sometimes called d- block elements.

p-orbital filled

Groups 3A - 8A

d-orbital filled

Groups 3B - 2B

increases left to right, decreases top to bottom, increases left bottom corner to top right

How does electronegativity work on the periodic table

When is an atom "ionized"?

If an electron is pulled toward another atom with enough energy to overcome the effective nuclear attraction of the parent atom holding the electron in the cloud, it can leave the atom completely. Once an electron has been removed from one atom and added to another, both atoms are changed.

Shielding affect with ionization energy

Inner electrons shield outer electrons from the positive nucleus. This means outer electrons are not held as tightly.

Law of Octaves

John Newlands proposed that the same properties appear every eighth element when the elements are listed in order of their atomic masses

How to determine the number of valence electrons?

Look at the GROUP NUMBER the element is in. Remember the GROUP NUMBER is the numbers 1 to 18 across the tops of the vertical columns. IGNORE the TRANSITION ELEMENTS (groups 3-12) for now. ONLY LOOK AT GROUPS 1, 2, 13, 14, 15, 16, 17 and 18.

properties of metals

Lustrous Have a shiny surface. Malleable Can be hammered thin. Ductile Can be stretched (wire) Good Conductors Allow heat and electricity to flow through easily. They are mostly solids at room temp. What is one exception? Mercury (Hg) is a LIQUID!

So why is Mendeleev called the "father of the modern periodic table" and not Meyer, or both?

Mendeleev stated that if the atomic weight of an element caused it to be placed in the wrong group, then the weight must be wrong. (He corrected the atomic masses of Be, In, and U) was so confident in his table that he used it to predict the physical properties of three elements that were yet unknown.

what kind of elements make up most of the periodic table?

Metals

Properties of nonmetals

Nonmetal properties are the basically opposite of metals: Dull Not shiny/can't be polished. Brittle Break easily...cannot be hammered thin. Poor/non-conductors Limited or no flow of heat or electricity through them. (also called insulators). Some are solid, several are gases, and BROMINE is a liquid.

atomic number

Number of protons (nucleus) or electrons (electron cloud).

subshells

Orbitals with different shapes occupy different regions. These regions are called

unit for electronegativity

Paulings

electron cloud levels

Principal energy level Sublevel Orbital

spin quantum number

The quantum number that has only two possible values, +1/2 and -1/2, which indicate the two fundamental spin states of an electron in an orbital

Hund's Rule

Single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals.

d^4 and d^9 rule

Sometimes an electron configuration will end with 4 or 9 electrons in the d-sublevel; these are unstable Will steal electrons from the s-sublevel before it to stabilize.

octet rule

The "goal" of most atoms (except H, Li, and Be) is to have a group of 8 electrons in their valence energy level. They may accomplish this by either giving electrons away or taking them. Metals generally give electrons, nonmetals take them from other atoms. Atoms that have gained or lost electrons are called ions.

Why does atomic radius decrease across a period?

The effect is that the more positive nucleus has a greater pull on the electron cloud. The nucleus is more positive and the electron cloud is more negative. The increased attraction pulls the cloud in closer to the nucleus, making atoms smaller as we move from left to right across a period.

Ionization energy

The energy required to remove an electron from an atom is always endothermic, that is energy is added to the atom to remove the electron.

f-orbital filled

The lanthanides and actinides

electron configuration

The ways in which electrons are arranged in various orbitals around the nuclei of atoms

groups/families

Vertical columns on the periodic table

Atom is larger and loses electrons easier

What happens if an electron is larger?

Anion

When an atom gains an electron, it becomes negatively charged (more electrons than protons )

why does the atomic radius increase in columns?

With each step down the family, we add an entirely new energy level to the electron cloud, making the atoms larger with each step.

Chemical symbol

a one or two-letter abbreviation for the name of an element based on the Greek or Latin name of element

metallic character

a relative measure of how easily atoms lose or give up electrons.

why are there electron configurations that are exceptions?

because half-filled sublevels are not as stable as filled sublevels, but they are more stable than other configurations. due to subtle electron-electron interactions in orbitals with very similar energies.

If an atom gains an electron it....

becomes NEGATIVELY charged

If an atom loses and electron....

becomes POSITIVELY charged

How to abbreviate electron configurations

by indicating the innermost electrons with the symbol of the preceding noble gas.

Halogen Triad

chlorine, bromine, iodine

Johann Dobereiner

classified some elements into groups of three, which he called triads. one was called halogen triad(Cl, Br, I) first to try to organize the elements based on their properties

Atomic mass

combined number of protons and neutrons in the nucleus.

shape of p orbital

dumbbell(can be Px, Py, and Pz)

polar covalent bond

electronegativity-0.5−1.7 2 nonmetals, electrons unequally

semiconductor

elements that have conduction capacities between non metals and metals.

Hydrogen

in a group all by itself. With its electron configuration of 1s 1 it can either give an electron away or gain an electron. In this respect,it can act as a metal or a nonmetal. It usually shares its electron. It reacts quickly with other molecules or forms H2. It's the only nonmetal on the left side of the table.

anions are always larger than the original atom.

ionic radius for anions

Cations are always smaller than the original atom.

ionic radius for cations

Heisenberg uncertainty principle

it is impossible to know exactly both the velocity and the position of a particle at the same time Since electrons are moving so fast, we can never know their exact position.

Cation

metal atoms can lose electrons. They become positively charged

Overall reactivity trend for metals

most reactive-the largest since they are the best electron givers

Overall reactivity trend for nonmetals

most reactive-the smallest ones, the best electron takers.

noble gases

nonreactive gases, monoatomic, almost inert group in group 18

Atomic orbital

often thought of as a region of space in which there is a high probability of finding an electron

Dmitri Mendeleev

published a table of the elements organized by increasing atomic mass. discovered periodic law observed that element properties repeated in a regular pattern predicted that the blank spaces in his Periodic Table were undiscovered elements.

Periods

rows on the periodic table

sublevels and orbitals

s, p, d, f s had lowest energy and f has highest

properties of metalloids

semi-metals have characteristics of both metals and nonmetals. shiny but brittle. semiconductors What are our most important semiconductors? Silicon, Germanium, and Arsenic.

shape of s orbital

spherical

angular momentum(azimuthal) quantum number

symbolized by l, indicates the shape of the orbital

magnetic quantum number

symbolized by m, indicates the orientation of an orbital around the nucleus

principal quantum number

symbolized by n, indicates the main energy level occupied by the electron

What is electron affinity?

the energy change that occurs when an atom gains an electron (also measured in kJ). usually exothermic, but not always

where does the modern quantum mechanical model come from?

the mathematical solutions to the Schrödinger equation.

Element name

the name of the element.

periodic law

the physical and chemical properties of the elements are periodic functions of their atomic numbers When arranged by increasing atomic number, the chemical elements display a regular and repeating pattern of chemical and physical properties.

Principal energy levels

there are 7 each row represents 1

what are valence electrons used for?

to bond to other atoms to form COMPOUNDS.

Quantum number

used to describe the probable location of electrons

When does atomic radius increase on the periodic table of elements?

vertical columns(groups/families) of the periodic table

Glenn T. Seaborg

~Moved 14 elements out of the main body of the periodic table to form the "Actinide" series ~Co-discovered 10 new elements