BPED4004 – Bioscience 4: Course Basics & Atoms and Bonding

30 question-and-answer flashcards summarizing course administration details, lab safety, Unitec values, and key concepts from the Atoms & Bonding section of BPED4004 – Bioscience 4.

Define an isotope.

Atoms of the same element (same protons) that contain different numbers of neutrons.

Why do atomic masses on the periodic table contain decimal values?

They are weighted averages of the naturally occurring isotopes of each element.

Across a period (row) of the periodic table, how do elements change?

They increase in atomic number and fill their outer (valence) electron shell progressively.

What common characteristic is shared by elements within the same group (column)?

They have the same number of valence electrons and therefore similar chemical reactivity.

How many electrons can occupy the first three shells discussed in this course?

First shell 2, second shell 8, third shell 8.

What is a valence electron?

An electron located in the outermost shell of an atom that is involved in chemical bonding.

How do atoms with one or two valence electrons usually achieve stability?

By giving away their valence electrons to form positive ions (cations).

How do atoms with nearly full valence shells typically achieve stability?

By gaining electrons to complete the shell, forming negative ions (anions).

State one key difference between a compound and a mixture.

In a compound, elements are chemically bonded and cannot be separated physically, whereas in a mixture components are only physically combined and can be separated.

Describe covalent bonding.

A type of chemical bond in which atoms share pairs of electrons to fill their valence shells.

Describe ionic bonding.

A bond formed when one atom transfers electrons to another, producing oppositely charged ions (cations and anions) that attract each other.

What is a cation?

A positively charged ion formed when an atom loses one or more electrons.

What is an anion?

A negatively charged ion formed when an atom gains one or more electrons.

For an ionic compound to be electrically neutral, what must occur?

The total positive charge of the cations must balance the total negative charge of the anions.

What diagrammatic tool is commonly used to show valence electrons and bonding patterns?

Lewis (electron-dot) structures.

Why do electrons pair with opposite spins in an orbital?

To minimize repulsion and satisfy the Pauli exclusion principle; one electron spins up, the other spins down.

What is an Atom?

An atom is the smallest unit of an element, consisting of a nucleus containing protons and neutrons, surrounded by electrons in specific energy levels.

what is a compound?

A compound is a substance formed when two or more elements chemically bond together what is a mo

what is a molecule?

A molecule is a group of two or more atoms bonded together, representing the smallest fundamental unit of a chemical compound.

what is a atomic number?

The atomic number is the number of protons in the nucleus of an atom, which determines the element's identity and its position in the periodic table.