The atom: Properties, Isotopes, and Ions

1 AMU =

1 DA (Dalton)

The Nuclear Force is the

force within the nucleus that pulls together protons and neurons (opposites attract)

For a neutral element, often called an atom, the number of ___&___ are equal

protons and electrons

Mass number (A)

provides the number of protons plus neurons

Atomic number (z)

provides the number of protons.

What does the atomic number (z) determine?

It determines the identity and chemical properties of an element.

1 AMU is

1.66*10^-27 kg OR 1.66054*10^-29g

What is the atomic mass formula?

Atomic mass= [(Isotope mass 1)]*(fractional abundance)]+[(isotope mass 2)*(fractional abundance)]

What is an isoelectronic?

Elements that have the same number of electrons

How to calculate the number of neutrons?

Mass number (a)-atomic number (z)

Nucleus is

The center of an atom that possesses the 2 subatomic particles of neutrons and protons

Which of the following statements are true? A) Protons and electrons have charges of the same magnitude but opposite signs B) The number of protons must be equal to the number of neurons within the atom C) The atom is best described as a uniform sphere of matter in which electrons are embedded D) The volume of the nucleus is a very large fraction of the total volume of the atom

The correct answer is A: Protons and electrons have charges of the same magnitude but opposite signs A) Same magnitude (+1 and -1 charge) and opposite signs (positive and negative) B) Must is wrong. Number of protons will not always be equal to number of neurons. Ex. 5 protons and 6 neurons C)Uniform sphere is not true. Atom has the nucleus, electrons, and other parts D) The volume of the nucleus is a not a very large fraction -it's a very small fraction of the total volume.

What are the two major forces that characterize the behavior between protons and neurons?

The nuclear force and electrostatic force.

What has to be greater for a stable nucleus to be held together?

The nuclear force has to be greater than the electrostatic force.

Neutrons are

The subatomic particles that carry no charge and found within the nucleus

Protons are

The subatomic particles that carry positive charge and found within the nuclus

What is an anion?

When an element gains electrons it becomes negatively charged.

What is a cation?

When an element loses electrons it becomes positively charged

Atomic masses of an element is an average of

all isotopes that uses the units of g/mole, amu, or Da

Isotopes

are the elements with the same number of protons but different numbers of neurons

Ions are

created from the loss or gaining of electrons by elements

Fractional abundance represents the

percent abundance of an isotope divided by 100.

AMU is

shorthand for atomic mass unit and is used to calculate the relative mass of an atom or subatomic particle.

Electrons are

the smallest subatomic particles that carry negative charge and spin around the nucleus

The electrostatic force is the

within the nucleus that pulls apart protons and neutrons (same charges repel one another)