Chemistry Midterm Review Chapter 3 Fall 2023

Part 1

100

Which of the following statements is true according to modern atomic theory? 

Atoms of the same element may have different masses.

Atoms may be divided in ordinary chemical reactions.

Atoms can never combine with any other atoms.

Cathode rays are composed of protons.

Atoms of the same element may have different masses.

200

Which concept in Dalton's atomic theory has been modified?

Atoms cannot be divided. Or atoms have isotopes.

300

The atomic theory proposed by Dalton has been

 expanded or modified.

400

In early experiments on electricity and matter, an electrical current was passed through glass tube containing 

gas under low pressure

500

The rays produced in a cathode tube are

deflected away from a negative plate.

Part 2

100

After measuring the ratio of the charge of a cathode-ray particle to its mass, Thomson concluded that particles 

have very small mass.

200

A positively charged particle with mass 1.673x10^(-24)g is a(n)

proton

300

In Rutherford's experiments, most of the particles

passed through the foil

400

Rutherford's experiments led him to conclude that atoms contain massive central regions that

have a positive charge

500

The nucleus of an atom has all the following characteristics except that it 

is positively charged, very dense, contains nearly all of the atom's mass, or contains nearly all the volume of the atom

volume

Part 3

100

The radius of an atom extends to the outer edge of the

electron cloud

200

Isotopes are atoms of the same element that have different

masses

300

As the mass number of an element's isotopes of an element increases, the number of protons

remain the same

400

In determining the atomic mass of elements, the standard is the

C-12

500

The average atomic mass of an element is the average of the atomic masses of its

naturally occuring isotopes

Part 4

100

The atomic mass of an element listed in the periodic table is the

average atomic mass

200

Phosphorus-33 (atomic number 15) contains

15 protons, 18 neutrons and 15 electrons

300

What is Avogadro's number?

6.022x10²³

400

Molar mass

is the mass in grams of 1 mole of a substance. and is numerically equal to the avg atomic mass of the element.

500

The mass of 1 mol of chromium (atomic mass 51.966 amu) is

51.966 g/mol