unit 1 atoms and molecules Flashcards
What are the smallest, most fundamental material components of the human body?
Chemical elements
Elements such as phosphorus, carbon, sodium, and calcium originated in stars.
How is matter defined by scientists?
Anything that occupies space and has mass.
What is an element?
A pure substance that cannot be created or broken down by ordinary chemical means.
What are the four most abundant elements in the human body?
- Oxygen (O)
- Carbon (C)
- Hydrogen (H)
- Nitrogen (N)
What is a compound?
A substance containing at least two different elements joined by chemical bonds.
What is an inorganic compound?
A substance that does not contain both carbon and hydrogen.
What is an organic compound?
A substance that contains carbon-hydrogen bonds.
What is the role of carbon in organic molecules?
Carbon can bind to other carbon atoms and atoms of other elements in multiple ways.
What is ATP and its significance?
Adenosine triphosphate, vital for the functioning of human cells.
What is an atom?
The smallest quantity of an element that retains the unique properties of that element.
What are the three important subatomic particles in an atom?
- Protons
- Neutrons
- Electrons
What determines the atomic number of an element?
The number of protons in the nucleus of the atom.
What is the mass number of an atom?
The sum of the number of protons and neutrons in its nucleus.
What does the periodic table represent?
It identifies elements in order of atomic number and provides their chemical symbol and mass number.
What is a valence shell?
An atom’s outermost electron shell.
What is the octet rule?
Atoms are most stable with eight electrons in their valence shell.
What happens to an atom that loses or gains electrons?
It becomes an ion, either positively or negatively charged.
What is a cation?
A positively charged ion.
What is an anion?
A negatively charged ion.
What is an ionic bond?
An ongoing association between ions of opposite charge.
What is the relationship between potassium and its ionic form?
Potassium donates one electron to become a cation (K+).
What does fluorine become when it accepts an electron?
Fluoride (F–), a negatively charged ion.
What is the significance of the number of electrons in the valence shell?
It governs the tendency of an atom to participate in chemical reactions.
What common compound is formed from the ionic bond between sodium and chlorine?
Table salt (NaCl).
