Unit 5 Chemistry Study Guide

What was inadequate about Rutherford's atomic model?

Rutherford's model couldn't explain the chemical properties of elements.

Where are the representative elements?

S and P blocks (not noble gases)

Describe Bohr's model of the atom. What is the limitation of Bohr's model?

The Bohr Model is a planetary model in which the negatively charged electrons orbit a small, positively charged nucleus similar to the planets orbiting the sun. His model only worked with hydrogen atoms. It failed with other atoms.

Where are the metals located on the Periodic Table?

The left side

What determines the type of decay that a radioisotope undergoes?

The neutron-to-proton ratio in a radioisotope

Compare Bohr's model of an atom to standing on a ladder.

The orbits/level of Bohr's model are like the rungs/steps in a step ladder. Cannot stand between rungs, electrons can't exist between levels/orbits. The smaller the e- orbit, the lower the energy state/level. The larger the e- orbit, the higher the energy state/level.

What is nuclear radiation?

The particles and photons emitted during reactions that involve the nucleus of an atom.

Periodic Law

The physical and chemical properties of element are periodic (repeating) functions of their atomic number. This means that when elements are arranged in order of increasing atomic number, elements with similar properties appear at regular intervals.

Where are the nonmetals located on the Periodic Table?

The right side

What is the nuclear band of stability?

The stability of elements determined by the ratio of the number of neutrons to the number of protons in the nucleus.

Johann Dobereiner

Tried to group elements into groups of 3 with similar properties. Worked for some groups but was not workable for the majority of elements known at the time.

What is the wavelength and frequency of a wave?

Wavelength- the distance between two consecutive wave peaks. Frequency- how many wave peaks pass a certain point per given time period.

What is a line emission spectrum? How does this compare to a continuous spectrum?

When an electric current passes through a gas, it gives energy to the gas and this energy is then given out as light of several definite wavelengths (colors) In a line emission spectrum, there can be isolated emission lines with huge gaps between them, but in a continuous spectrum there aren't any gaps.

What is an energy level?

fixed distances from the nucleus of an atom where electrons may be found.

What groups are the transition metals?

Groups 3-12

What is the order of filling orbitals based on?

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p

What is the accepted speed of light?

3.00 x 10^8 m/s

What is Planck's constant?

6.626 x 10^-34 J

What is a decay series?

A series of decay in which radioactive element is decomposed in different elements until it produces one stable atom.

What are the 5 main types of radiation and how do they differ from one another?

Alpha, Beta, Gamma, Positron, Electron Capture Differ in mass and energy.

What was the Black Body Radiation Experiment?

An idealized object that absorbs all electromagnetic radiation that falls on it. No electromagnetic radiation passes through it and none is reflected. In this experiment, an object that was heated to emit the light which was analyzed for wavelength and frequency of emissions. Planck found that energy was not continuous but quantized and could only be absorbed or emitted in whole-number multiples of these packets.

Alexandre-Émile Beguiler de Chancourtois

Arranged the elements in order of increasing atomic weights

Increase or decrease Atomic Radii: Left to Right- Top to bottom- Ionic Radii: Left to Right- Top to bottom- Electron Affinity: Left to Right- Top to bottom- Ionization Energy: Left to Right- Top to bottom- Electronegativity: Left to Right- Top to bottom-

Atomic Radii- decrease, increase Ionic Radii- decrease, increase Electron Affinity- increase, decrease Ionization Energy- increase, decrease Electronegativity- increase, decrease

Explain atomic spectra using concepts of ground state, excited state, photon and emission by electron transition and how this demonstrates electron energy levels.

Atoms start at a ground state and when atoms are excited they move to an excited state and emit light of certain wavelengths which correspond to different colors.

What are the 3 rules governing electron configuration and what do they specify?

Aufbau Principle- an electron will occupy the lowest energy configuration available to it. Hund's Rule- Orbitals of equal energy are each occupied by one electron before any orbital can be occupied by a second electron. All electrons in single-occupied orbitals have same spin. Pauli Exclusion Principle- No two electrons in the same atom can have the same set of 4 quantum numbers. Principle, angular momentum and magnetic quantum numbers specify the energy, shape, and orientation of an orbital. Spin allows 2 electrons of opposite spin to occupy the same orbital.

What are the 2 ways that transmutations can occur?

By radioactive decay or when particles bombard the nucleus of an atom.

Lothar Meyer

Compiled a table of 56 elements based on the periodic (repeating) properties when elements were arranged by increasing atomic weight.

Aristotle

Created the theory that all matter was composed of combination of 4 "elements": Earth, Air, Fire, and Water.

What were the contributions of DeBroglie, Heisenberg and Schrodinger?

DeBroglie- Worked on the question of why an electron can only occupy specific orbits around the nucleus of an atom. Heisenberg- Said that you can know either the location or momentum of an electron at any given point in time, but not both at the same time. Schrodinger- developed an equation to describe the location of electrons within the electron cloud of an atom.

What is the quantum mechanical model of the atom?

Determines the allowed energies an electron can have and how likely it is to find the electron in various locations around the nucleus.

Jöns Jakob Berzelius

Developed a table of atomic weights and introduced letters to symbolize elements.

Stanislao Cannizzaro

Developed a workable method to accurately measure the atomic masses of elements.

Glenn Seaborg

Did the last "tweak" to the structure of the Periodic Table. Proposed moving the inner transition elements (lanthanide and actinide series) out of the main body of the Periodic Table to allow the original structure of the table to be reestablished.

William Ramsay

Discovered Noble gases (column 18)

What are the transuranium elements?

Elements with atomic numbers greater than 92

The columns of the Periodic table are called

Families

What forms of electromagnetic radiation make up the electromagnetic spectrum? (from highest to lowest)

Gamma rays X rays Ultraviolet Visible Light Infrared Microwaves Radiowaves

What group is the alkali metals?

Group 1

What group is the halogens?

Group 17

What group is the noble gases?

Group 18

What group is the alkaline earth metals?

Group 2

What does the line emission spectrum for hydrogen look like?

It gives off a violet, blue, green, and red color.

What is the order of all the scientists?

Lavoisier, Berzelius, Dobereiner, Cannizzaro, Beguyer de Chancourtois, Newlands, Meyer, Mendeleev, Ramsay, Moseley, Seaborg

What is meant by the dual wave-particle of nature of light?

Light behaves as a wave.

Henry Moseley

Listed elements in order of increasing nuclear charge which caused the elements to better fit into patterns of similar chemical properties. HIs work led to modern definition of atomic number and recognition that atomic number is the basis for the organization of the periodic table.

What type of EM radiation has the longest/shortest wavelength? Highest/lowest energy and frequency?

Longest wavelength- Radiowaves Shortest wavelength- Gamma rays Highest energy- Gamma rays Lowest energy- Radiowaves Lowest frequency- Radiowaves Highest frequency- Gamma rays

What color of visible light has the longest/shortest wavelength? Highest/lowest energy?

Longest wavelength- Red Shortest wavelength- Violet Highest energy- Violet Lowest energy- Red

What is the normal and exception electron configuration of Cr and Cu?

Normal Cr: [Ar] 4s^2 3d^4 Normal Cu: [Ar] 4s^2 3d^9 Exception Cr: [Ar] 4s^1 3d^5 Exception Cu: [Ar] 4s^1 3d^10

What is nuclear fission? What is it used for? What is a chain reaction?

Nuclear fission- When the nucleus of a very heavy atom splits into more stable nuclei of smaller mass. This process releases a great deal of energy, and is the basis for nuclear reactors and some low-energy atomic weapons. Chain reaction- occurs when the material starts the reaction is also one of the products of the reaction and can start another reaction.

What is nuclear fusion? What is solar fusion? Why is fusion difficult to replicate on earth?

Nuclear fusion- Smaller atomic nuclei are joined, or fused, together to form a nucleus of greater mass. Solar fusion- the process that powers the sun and the stars. Fusion is difficult to replicate on earth because the strongly repulsive electrostatic forces between the positively charged nuclei prevent them from getting close enough together to collide and for fusion to occur.

Where are the metalloids located on the Periodic Table?

On either side of the dividing line between metals and nonmetals

Compare an orbit to an orbital.

Orbit- defined circular path around the nucleus Orbital- Probable area of finding the electrons around the nucleus

What are parent and daughter nuclides?

Parent nuclide- The heaviest radioisotope of each decay series. Daughter nuclide- The radioisotopes produced by the decay of the parent nuclide.

Where are the Lanthanides located on the Periodic Table?

Period 6

Where are the Actinides located on the Periodic Table?

Period 7

The rows of the periodic table are called

Periods

What are the contributions of both Planck and Einstein?

Planck- developed an equation to determine the amount of energy absorbed or emitted by an object in his Black Body Radiation Experiment Einstein- used Planck's quantum theory to describe the particle properties of light

What are the 4 quantum numbers and what do they represent?

Principle Quantum Number- describes the energy level of the electron. Angular Momentum Quantum Number- describes the shape of the orbital in space. Magnetic Quantum Number- describes the orientation of the orbital in space. Spin Quantum Number- describes the 2 possible directions of electron spin (clockwise and counterclockwise)

Dmitri Mendeleev

Produced a table based on atomic weights but arranged "periodically" with elements with similar properites under each other. Gaps were left for elements that were unknown at the time and he predicted in 1871 the properties for three of them- gallium, scandium, and germanium. He re-arranged the order of some of the elements to not follow increasing atomic weight if their properties did not line up. The discovery of the three predicted elements convinced scientists to accept his table.

John Newland

Proposed a "Law of Octaves" to order the elements, He noticed that when the elements were arranged by atomic weight, certain chemical properties began to repeat themselves roughly every 8 elements.

Antoine Lavoisier

Wrote the first extensive list of all known elements (33 at the time) and distinguished between metals and nonmetals.

Do all forms of light travel at the same speed?

Yes

What is the formula for speed?

speed = wavelength x frequency

What is the photoelectric effect?

the ability of light to cause matter to move

What is a half-life?

the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay.