Chemistry First Semester Final Practice Test - Period 4

Front

Which scientist's model of the atom is often described as the 'plum pudding' model?

Back

J.J. Thomson's model describes the atom as a sphere of positive charge with negatively charged electrons embedded within it, resembling a plum pudding.

Front

How many significant figures are in the measurement 2.03 m?

Back

There are 3 significant figures in the measurement 2.03 m.

Front

How does the number of electrons in a neutral atom relate to its position on the periodic table?

Back

In a neutral atom, the number of electrons equals the atomic number, which determines the element's position on the periodic table.

Front

What is the charge of a proton?

Back

The charge of a proton is +1.

Front

The anion form of an atom is always ___________ than its neutral form.

Back

Larger. An anion is formed when an atom gains one or more electrons, resulting in a negative charge and an increase in size.

Front

What is the atomic number of an element?

Back

The atomic number is the number of protons in the nucleus of an atom, which also equals the number of electrons in a neutral atom.

Front

Define mass number.

Back

The mass number is the total number of protons and neutrons in an atom's nucleus.

Front

What is the charge of an electron?

Back

The charge of an electron is -1.

Front

What is the difference between an atom and an ion?

Back

An atom is neutral, having equal numbers of protons and electrons, while an ion has a net charge due to the loss or gain of electrons.

Front

What is the significance of the periodic table's groups?

Back

Elements in the same group have similar chemical properties and the same number of valence electrons.