Subatomic Particles and Atomic Models flashcard

Flashcards covering the key concepts related to subatomic particles, atomic models, ions, isotopes, atomic mass, and properties of elements in the periodic table.

What did J. J. Thomson discover in 1897?

Thomson discovered the electron.

What is the charge of an electron?

-1.60 x 10^-19 coulombs.

What experiment did Ernest Rutherford conduct in 1909?

The gold foil experiment.

What was John Dalton's theory regarding atoms?

Atoms are indivisible and those of a given element are identical.

What model did Thomson propose for the atom?

The plum pudding model.

How did Rutherford’s gold foil experiment contribute to atomic theory?

It revealed that the atom is mostly empty space with a concentrated positive charge in the nucleus.

What did Niels Bohr modify in Rutherford’s model?

Bohr proposed that electrons move around the nucleus in fixed orbits.

According to Schrödinger, how do electrons move around the nucleus?

Electrons move in clouds of probability and do not follow set paths.

What is the atomic number represented by in an element?

The number of protons in an atom's nucleus.

What are ions?

Atoms with the same number of protons but a different number of electrons.

What is an example of a cation?

Li+ or Mg2+.

What are isotopes?

Atoms with the same number of protons but different numbers of neutrons.

What is the mass number (A)?

The sum of the number of protons and neutrons in an atom.

How is atomic mass calculated?

It's the weighted average of the masses of its isotopes.

What is a characteristic of elements in the same group of the periodic table?

They tend to have similar properties.

What are the characteristics of Group 1A elements?

They are alkali metals and very reactive.

What are noble gases?

Elements in Group 8A that are mostly unreactive.

What is the key difference between protons and electrons?

Protons are positively charged and located in the nucleus, while electrons are negatively charged and orbit the nucleus.

What is the role of neutrons in an atom?

Neutrons have no charge and contribute to the atom's mass within the nucleus.

What is an anion?

An atom with the same number of protons but a greater number of electrons, resulting in a negative charge.

What are groups (or columns) in the periodic table?

Vertical columns containing elements with similar chemical properties.

What are periods (or rows) in the periodic table?

Horizontal rows where element properties gradually change across the row.

What is an atom?

The basic unit of matter, consisting of a dense nucleus surrounded by a cloud of negatively charged electrons.

What is the charge of a proton?

+1.60 \times 10^{-19} coulombs, which is equal in magnitude but opposite in sign to the charge of an electron.

What is the charge of a neutron?

Neutrons have no electric charge (they are neutral).

What is the significance of the atomic number (Z)?

The atomic number determines the identity of an element, as it uniquely specifies the number of protons in its atoms.

What is the atomic mass unit (amu)?

A unit of mass used

What is the atomic mass unit (amu)?

A unit of mass used to express atomic and molecular masses. It is defined as 1/12 the mass of an unbound atom of carbon-12.

What are the approximate relative masses of protons, neutrons, and electrons?

Protons and neutrons have approximately the same mass (about 1 amu), while electrons are much lighter, approximately 1/1836 the mass of a proton.

Where are protons, neutrons, and electrons located within an atom?

Protons and neutrons are found in the dense central nucleus, while electrons orbit the nucleus in electron shells or clouds of probability.

What was a key assertion of John Dalton's atomic theory regarding the nature of atoms?

Atoms are indivisible and those of a given element are identical.

What subatomic particles are found in the atomic nucleus?

Protons and neutrons.

How does an atom become a cation?

An atom becomes a cation by losing electrons, resulting in a net positive charge.

If an atom has 6 protons and 7 neutrons, what is its mass number (A)?

The mass number (A) is the sum of protons and neutrons, so A = 6 + 7 = 13.

What generally happens to the properties of elements as you move across a period (row) in the