Atomic Structure (Module 3)

According to Democritus, all forms of matter are composed of tiny particles called _________

• atoms.

• electrons.

• neutrons.

• protons.

The nucleus is composed of ___________________

• electrons and neutrons.

• protons and electrons.

• protons and neutrons.

• protons, electrons and neutrons.

The atomic number gives the number of __________ in an atom.

• electrons

• neutrons

• electrons and protons

• protons and neutrons

All of the following characterize a proton except:

• It has no charge.

• It is positively charged.

• It is found in the nucleus.

• It has a mass equal to that of the neutron.

Which statement best describes electrons?

• They are positive subatomic particles and are found in the nucleus.

• They are positive subatomic particles and are found surrounding the nucleus.

• They are negative subatomic particles and are found in the nucleus.

• They are negative subatomic particles and are found surrounding the nucleus.

If the atomic number of an element is 6 and its mass number is 13, how many neutrons are contained in the nucleus?

• 6

• 7

• 8

• 13

Isotopes are atoms with a variable number of _____

• electrons.

• protons.

• ions.

• neutrons.

If an element is described by these data: Z=19 and A=40, which of the following statements is true of the elements?

• It has 19 protons and 20 neutrons.

• It has 19 protons and 19 neutrons

• It has 21 electrons and 19 protons.

• It has 19 electrons and 21 neutrons.

An atom has an atomic number of 11 and a mass number of 23. Which of the following statements is correct?

• The atom has 11 electrons and 11 neutrons.

• The atom has 11 electrons and 11 protons.

• The atom has 11 electrons and 12 neutrons.

• The atom has 12 electrons and 11 neutrons.

The mass number of isotopes are ____________

• equal.

• different.

• divisible by each other.

• in a small whole number ratios.