1 1 atomic structure

The key ideas of Dalton's atomic theory are:

An atom is a tiny particle that makes up matter.

True. Different atoms combine together to form new substances.

A scientific model can be changed or replaced when new experimental evidence improves our understanding.

A proton has a relative mass of 1 and a charge of +1.

True. All atoms of the same element have the same number of protons.

An electron has a negligible mass and a charge of -1.

The subatomic particles in the nucleus of an atom are protons and neutrons.

To calculate the number of neutrons in an atom:

True. Atoms are made of subatomic particles including protons, neutrons, and electrons.

The subatomic particle with a mass of 1 and a charge of 0 is the neutron.

The number of electrons in an atom is the same as the number of protons / the atomic number.

Atoms are electrically neutral because they have the same number of electrons as protons.

False. Electrons have a much smaller mass than protons.

The sub-atomic particle that is not found inside the nucleus is the electron.

The nucleus is the central part of the atom.

The atomic number is the number of protons (in the nucleus of an atom).

The mass number is the total number of protons and neutrons (in the nucleus of an atom).

Most of the mass of an atom is in the nucleus.

False. The nucleus of an atom is very small compared to the overall size of the atom.

Atoms of the same element have the same:

False. The atomic number is unique to an element.

Elements like chlorine and copper do not have whole numbers for their atomic mass because of isotopes.

An isotope is an atom of the same element containing the same number of protons but different numbers of neutrons.

The number of protons, neutrons and electrons in are:

Number of neutrons = mass number - atomic number.

Isotopes have the same symbol and same atomic numbers but different mass numbers.

The isotopes are and . is not an isotope because it is a different element (nitrogen not carbon).

False. Isotopes display the same chemical characteristics.

The chemical characteristics of an atom are determined by the number of electrons in the outer shell.

The number of protons is the atomic (proton) number.

The difference between isotopes of the same element is the number of neutrons.

In a neutral atom, the number of electrons is equal to the number of protons, which is the atomic number.

The number of protons, neutrons and electrons in are:

False. Mass number and relative atomic mass are not the same. Relative atomic mass is an average of all isotopes.

Two pieces of information required to calculate the relative atomic mass of an element are:

The equation for calculating relative atomic mass in terms of the percentage abundance and mass of isotopes A and B is:

False. The relative atomic mass of an element is calculated using the mass numbers and relative abundances of all its isotopes.

The relative atomic mass of the element is: = 69.8 or 70

In terms of isotopes, abundance is the amount of each isotope present in a sample of an element.

False. Relative atomic mass is calculated by:

After calculating the Ar, you would identify an element by looking for the value on the Periodic Table. For example, Ar = 23. On the Periodic Table, the element with an Ar of 23 is sodium.

The relative atomic mass of the element is: = 35.5