Honors Chemistry Unit 2 Test

Democritus

Democritus

Greek philosopher who was among the first to suggest the existence of atoms. (believed that atoms were indivisible and indestructible)

Aristotle

Greek philosopher- believed that matter is infinitely divisible.  Matter is composed of earth, wind (air), fire, water

Dalton

English chemist and schoolteacher who formulated a theory to describe the structure and chemical reactivity of matter in terms of atoms

Thomson

Discovered the Electron using the Cathode Ray Tube. Introduced the “Plum Pudding” model.

Rutherford

Discovered the nucleus of the atom using the Gold Foil Experiment

Millikan

Determined the mass and measured the charge of an electron using the Oil Drop Apparatus (1/1840 the mass of a hydrogen atom)

Chadwick

Confirmed the existence of the Neutron. Preformed the first artificial nuclear transformation, and the first artificial nuclear transformation

Goldstein

Observed that proton particles have a relative mass of 1

Schrödinger

Developed the equation for the probability of a single electron being found along a single axis. (he showed, through math, that waves can be used to describe electrons in atoms)

de Broglie

1929 discovery that electrons have properties of both waves and particles

Bohr

Created the Bohr model of the atom. It demonstrated that electrons occupy orbits at specific energies, Explained hydrogen spectral lines, and how electrons can be moved to a higher or lower energy level by the absorption or emission of energy (quantum leaps)

Heisenberg

Heisenberg’s uncertainty principle: It is impossible to know the exact location and velocity of an electron. The better we know one, the less we know the other.

Planck

The father of the quantum theory of energy. Planck’s Constant = 6.63 × 10^-34; He determined that atoms can emit quanta, which is the plural of quantum

Who found 1st subatomic particle - proving the atom is NOT the smallest particle of matter

Thompson

Bohr Model

An early model of atomic structure in which electrons travel around the nucleus in a number of stable orbits and electrons jump from one orbit to another based on conditions.

Cathode Ray Experiment

Cathode ray tubes pass electricity through a gas that is contained at a very low pressure

Still Valid?:

All elements are composed of indivisible particles called atoms

Still Valid

Still Valid?:

Atoms of the same element are identical. Atoms of any one element are different from those of any other element.

Still Valid

Still Valid?:

Atoms of different elements combine in simple whole-number ratios to form chemical compounds

Still Valid

Still Valid?:
In chemical reactions, atoms are combined, separated, or rearranged – but never changed into atoms of another element.

Still Valid

Still Valid?:

All atoms of the same element have the same mass.

Not Valid

Who discovered the Laws of Definite/Indefinite Properties

Dalton

What is the Law of Definite Proportions

a chemical compound will always have the same proportions or amount of each element by weight, no matter what the amount is, or source.

What is the Law of Multiple Proportions

whenever the same two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.

Protons

Located in the nucleus, positively charged, mass = 1 amu

Neutrons

Located in the nucleus, neutral charge, mass = 1 amu

Electrons

Located in the space around the nucleus, negatively charged, mass = 1/1840 amu

Nucleus

The positively charged center of the atom, consists of protons and neutrons, and it contains almost all of the atom’s mass.

Atomic Number

Number of protons in an atom

Mass Number

Total number of protons and neutrons in an atom

Isotopes

Two or more forms of one element that share the same number of protons, but have different numbers of neutrons

Atomic Mass

The weighted average of all naturally occurring isotopes of an element

Average Atomic Mass Formula

AAM = (RA1)(M1) + (RA2)(M2)…

s Orbital Shape/Location

Spherical shape with the nucleus as its center,

p Orbital Shape/Location

Two lobes that lie on either side of the plane and pass through the nucleus. (Dumbell Shaped)

d Orbital Shape/Location

Shaped like two perpendicular dumbbells that lie on either side of the plane and pass through the nucleus

f Orbital Shape/Location

F orbital is found to be tetrahedral in shape. In total, 17 electrons can be accommodated in an f orbital. 

Electron Configuration

describes where electrons are located around the nucleus of an atom. (Ex: electron configuration of lithium, 1s²2s¹)

Ground State

the lowest energy state of an atom or other particle.

Excited State

When an electron temporarily occupies an energy state greater than its ground state,

Heisenberg uncertainty principle

It is impossible to know the exact location and velocity of an electron. The better we know one, the less we know the other.

Aufbau principle

electrons enter the lowest energy level first.

Pauli Exclusion principle

Orbitals can only have two electrons at once, and they must have opposite spins

Hund’s Rule

When electrons occupy orbitals of equal energy, they don’t pair up until they have to.

What are the exceptions to the filling order of electron configuration

Chromium and Copper.

Chromium steals a 4s electron to make its 3d sublevel half full.

Copper steals a 4s electron to fill its 3d sublevel

Photoelectric effect

a phenomenon that occurs when light shone onto a metal surface causes the ejection of electrons from that metal

Valence Electrons

The electrons in an atom's outermost electron shell

Stable Electron Configurations

The most stable electron configurations occur in the noble gasses. (or the ones that have full energy levels)

Hydrogen Spectra

The line spectrum emitted by a hydrogen atom when an excited hydrogen atom returns to its ground state

Chlorine has two naturally occurring isotopes, Cl-35 and Cl-37. The atomic mass of chlorine is 35.45. Which of these two isotopes of chlorine is more abundant?

Chlorine- 35

Atom

the smallest particle of an element that retains the properties of that element

Atomic Mass Unit

one-twelfth the mass of a carbon atom having six protons and six neutrons

The range in size of most atomic radii is approximately

5  × 10^–11 m to 2  × 10^–10 m

Evidence about Dalton’s atomic theory has shown that

Atoms are divisible

Why did J. J. Thomson reason that electrons must be a part of the atoms of all elements?

Charge-to-mass ratio of electrons was the same, regardless of the gas used.

Which hypothesis led to the discovery of the proton?

When a neutral hydrogen atom loses an electron, a positively-charged particle should remain.

An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the element are ____.

76 protons and 76 electrons

Isotopes of the same element have different

Mass numbers

How many protons, electrons, and neutrons does an atom with atomic number 50 and mass number 125 contain?

50 protons, 50 electrons, 75 neutrons

Protium

1/1 H

Deuterium

2/1 H

Tritium

3/1 H

What unit is used to measure weighted average atomic mass?

amu

The atomic mass of an element depends upon the

mass and relative abundance of each isotope of that element

What is the relative charge of a proton?

1+

How many protons are present in an atom of Be-9?

4

Atomic Orbital

region of high probability of finding an electron

What is the lowest energy level called?

The ground state

Photon

discrete bundle of electromagnetic energy

Quantum

energy needed to move an electron from one energy level to another

Frequency

number of wave cycles passing a point per unit of time

Wavelength

distance between wave crests

Spectrum

separation of light into different wavelengths

Atomic Emission Spectrum

frequencies of light emitted by an element

What is the maximum number of d orbitals in a principal energy level?

5

What types of atomic orbitals are in the third principal energy level?

s, p, and d only

What is the number of electrons in the outermost energy level of an oxygen atom?

6

Which type of electromagnetic radiation includes the wavelength 10^-7m?

visible light

According to the Heisenberg uncertainty principle, if the position of a tiny moving particle is known, the

velocity of the particle cannot be exactly determined.

How can the position of a very tiny particle be determined?

by analyzing its interactions with another particle

In an s orbital, the probability of finding an electron a particular distance from the nucleus can best be determined by the

quantum mechanical model.

What frequency are 20 mm microwaves?

15 GHz

What is the wavelength of a 92.9 MHz radio wave?

3.2 m

All electromagnetic waves travel through a vacuum at

The same speed