4.1 - 4.2 Chem Studyguide

Ernest Rutherford and the Gold Foil Experiment

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Carbon has an atomic number of 6. Therefore, all neutral carbon atoms have ______ and ______.

- 6 electrons - 6 protons

Who is John Dalton?

- A meteorologist - Unlike Democritus, Dalton had experimental evidence to support his theory

Which of these statements about atoms are true?

- Atoms are mostly empty space containing fast-moving electrons. - Most of the mass of an atom is in its nucleus.

Who was Aristotle?

- Greek philosopher - Did not believe empty space couldn't exist - His views went unopposed for 2,000 years

Who was JJ Thompson and Cathode Ray Tube Experiment

- In the tube was an inert gas and two plates, a positive and a negative. The particles in the gas were attracted to the positive plate. Therefore the particles must have a negative charge (opposites attract). - Discovered the electron

Which describe J.J. Thomson's model of the atom?

- It describes the atom as spherical. - Its positive charge is uniformly distributed. - It is sometimes called the "plum pudding model."

What were Dalton's 4 Major points to his theory?

- all elements are composed of indivisible particles called atoms - atoms of the same element are identical. The atoms of any one element are different from those of another - Atoms of different elements move or combine into whole number ratios Ex: Oxygen combines with Hydrogen to form water which is a 2:1 ratio - Chemical reactions occur when atoms separate, join, or rearrange. In a chemical change atoms of one element never change into another.

The mass number ______.

- identifies each isotope of an element - is the sum of the number of protons and neutrons in a nucleus

Which equations are correct for atoms?

- number of protons = number of electrons - atomic number = number of protons

What did Democritus propose?

- the atoms that made up matter could not be created, destroyed, or further divided. - matter was made up of tiny particles called atomos (atoms) - matter was not infinitely divisible

Beryllium has an atomic number of 4. Therefore, a beryllium atom has _________ protons and _________ electrons.

4 and 4

An element consists of two naturally occurring isotopes with the following masses and abundances. What is the average atomic mass of the element?Isotope 1: 62.93 amu, 69.2%Isotope 2: 64.93 amu, 30.8%

63.5 amu

An element consists of two naturally occurring isotopes with the following masses and abundances. What is the atomic mass of the element? Isotope 1: 68.928 amu, 60.11%Isotope 2: 70.925 amu, 39.89% Multiple choice question.

69.72%

Which is the smallest particle of an element that retains the properties of the element?

Atom

Whose model of the atom has matter containing evenly distributed positive charges and electrons?

J.J. Thomson

Which is a subatomic particle carrying a charge of 1+?

Proton

What is known about isotopes?

They have different masses but the same chemical properties.

The weighted average mass of the isotopes of an element is the __________ ____________ of the element.

atomic mass

Which is the weighted average mass of the isotopes of an element?

atomic mass

Isotopes of an element have different _________ but the same chemical ___________.

atomic masses, chemical behavior

The number of protons in an atom is the ___________ ___________ .

atomic number

Democritus proposed that matter was made up of atoms, which could not be______________,______________ , or further divided.

created, destroyed

A negatively charged, fast-moving particle with an extremely small mass that is found in all forms of matter and moves through the empty space surrounding an atom's nucleus is called a(n) ____________.

electron

Which is a negatively charged, fast-moving particle with an extremely small mass that is found in all forms of matter and moves through the empty space surrounding an atom's nucleus?

electron

All atoms are made up of the three fundamental subatomic particles—_________ ,_______ , and _________.

electrons, protons, nuetrons

Which term is used for atoms with the same number of protons but different numbers of neutrons?

isotopes

The number that identifies each isotope of an element and is the sum of the number of protons and neutrons in the nucleus is the ________ number.

mass

A neutral, subatomic particle that has a mass nearly equal to that of a proton is a(n) _______________.

neutron

The extremely small, positively charged, dense center of an atom that contains positively charged protons and neutral neutrons is the____________.

nucleus

Which is the extremely small, dense center of an atom that contains the atom's positive charge and almost all of its mass?

nucleus

A subatomic particle carrying a charge of 1+ is a(n) ___________.

protons

The atomic number can be used to identify an atom because it is equal to the number of _____________, which is a unique number for each element.

protons

The atomic number, which is a unique number for each element, can be used to identify an atom because it is equal to the number of which subatomic particles?

protons

The atomic number is equal to the number of ___________in an atom. It is also equal to the number of ___________ in an atom.

protons, electrons

The subatomic particles located in the nucleus of the atom are the ___________ and neutrons. The subatomic particles that are found in the space surrounding the nucleus are the ___________.

protons, electrons