Unit 3 Test Review HSPS

Front

Two atoms of different elements will definitely have different numbers of what? Options: Nuclei, Protons, Neutrons, Electrons

Back

Protons

Answer explanation

Two atoms of different elements will have different numbers of protons, as the number of protons defines the element itself. Therefore, the correct answer is protons.

Front

An ion forms when an atom gains or loses: Protons, Neutrons, Electrons

Back

Electrons

Answer explanation

An ion forms when an atom gains or loses electrons. Gaining electrons creates a negative ion (anion), while losing electrons results in a positive ion (cation). Protons and neutrons do not change in this process.

Front

How does a neutral atom become an ion with a charge of 2+?

Back

Losing two electrons

Answer explanation

A neutral atom has equal numbers of protons and electrons. To become a 2+ ion, it must lose two electrons, resulting in a positive charge. Losing protons or neutrons would change the atom's identity or mass, not its charge.

Front

What does an alpha particle consist of?

Back

2 protons and 2 neutrons

Answer explanation

An alpha particle is made up of 2 protons and 2 neutrons, which is equivalent to a helium nucleus. This distinguishes it from other particles like electrons or protons alone.

Front

Isotopes are atoms that have different

Back

Mass numbers

Answer explanation

Isotopes are atoms of the same element that have different mass numbers due to varying numbers of neutrons. They do not differ in atomic number or element name, making 'mass numbers' the correct choice.

Front

How is a positively charged ion formed?

Back

An electron is lost

Answer explanation

A positively charged ion is formed when an electron is lost. Electrons have a negative charge, so losing one results in a net positive charge for the ion.

Front

Two atoms that have different numbers of protons are

Back

Different elements

Answer explanation

Atoms with different numbers of protons are classified as different elements. The number of protons defines the element, while ions and isotopes refer to variations in charge and neutron number, respectively.

Front

If neutral copper atom (atomic number 29) becomes an ion that has a charge of 2+, how many electrons does the resulting ion have?

Back

27

Answer explanation

A neutral copper atom has 29 electrons. When it becomes a 2+ ion, it loses 2 electrons, resulting in 29 - 2 = 27 electrons. Therefore, the ion has 27 electrons.

Front

Which phrase describes two atoms that are isotopes? Options: Same mass number, same atomic number; Same mass number, different atomic number; Different mass number, same atomic number; Different mass number, different atomic number.

Back

Different mass number, same atomic number

Answer explanation

Isotopes are atoms of the same element with the same atomic number (number of protons) but different mass numbers (due to varying numbers of neutrons). Therefore, the correct choice is 'Different mass number, same atomic number'.

Front

What information would allow you to determine whether two atoms are of the same or different elements?

Back

The number of protons in their nuclei

Answer explanation

The number of protons in an atom's nucleus determines its element. Atoms with the same number of protons are the same element, while different numbers indicate different elements. Thus, this is the key information needed.