Chemistry Of Life Flashcards
What is a chemical element?
A pure substance that consists entirely of one kind of atom
Elements are represented by one- or two-letter symbols, such as C for carbon and H for hydrogen.
What is the atomic number of an element?
The number of protons in the nucleus of an element
For example, carbon has an atomic number of 6.
What six elements make up about 99 percent of the mass of living things?
- Calcium
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
- Phosphorus
These elements are essential for life.
What are trace elements?
Elements that make up the remaining 1 percent of mass in living organisms
A lack of trace elements can stunt plant growth or damage developing organs in unborn animals.
What affects how atoms interact with each other?
The number of electrons in their outer shells
The outer shell can be thought of as the ‘face’ an atom shows to its neighbors.
What are isotopes?
Atoms of the same element that differ in the number of neutrons
For example, carbon-14 has 8 neutrons while all carbon atoms have 6 protons.
What is the mass number of an atom?
The total number of protons and neutrons in the nucleus
Isotopes are identified by their mass numbers.
What is atomic mass?
The weighted average of the masses of an element’s isotopes
The abundance of each isotope in nature is considered when calculating the average mass.
Do neutrons affect the chemical properties of an isotope?
No, neutrons do not affect the chemical properties
Isotopes have different masses but their chemical properties remain the same.
How many protons and electrons does Carbon-12 have?
6 protons and 6 electrons
Carbon-12 is one of the nonradioactive isotopes.
What is the relationship between protons and electrons in a neutral atom?
They are equal in number
This balance maintains electrical neutrality in the atom.
What is the smallest unit of most compounds?
A molecule
A molecule is formed when atoms are joined together by covalent bonds.
What type of bond is formed when atoms share one electron from each atom?
A single covalent bond
This type of bond involves the sharing of one pair of electrons.
In a water molecule, how many electrons does each hydrogen atom share?
Two electrons
Each hydrogen atom in a water molecule shares one electron with oxygen.
What bond is formed when one atom loses an electron and another atom gains it?
An ionic bond
This bond involves the transfer of electrons, resulting in oppositely charged ions.
What happens to a neutral atom that loses electrons?
It becomes positively charged
A neutral atom loses its electrical neutrality and becomes a cation.
How are covalent bonds different from ionic bonds?
Covalent bonds involve sharing electrons, while ionic bonds involve transferring electrons
The nature of electron interaction differentiates the two types of bonds.
Fill in the blank: The electrons in an atom’s outer shell that are available to form bonds are called _______.
valence electrons
Valence electrons play a critical role in bond formation.
True or False: Ionic bonds form between atoms of the same charge.
False
Ionic bonds form between oppositely charged ions.
What do you call atoms that have gained or lost electrons?
Ions
Ions can be positively charged (cations) or negatively charged (anions).
What type of bond is formed when atoms share four electrons?
A double bond
A double bond involves the sharing of two pairs of electrons.
What type of bond is formed when atoms share six electrons?
A triple bond
A triple bond involves the sharing of three pairs of electrons.
What are van der Waals forces?
Weak attractions between molecules when they are very close together
Van der Waals forces are crucial for interactions among molecules in living cells, allowing for temporary connections that facilitate various biological processes.
What is the role of weak interactions in living cells?
They allow molecules to interact briefly for signaling, chemical reactions, or information transfer
Weak interactions are crucial for processes like enzyme activity and cellular communication.
What is a hydrogen bond?
A weak bond formed between a hydrogen atom of one molecule and an oxygen or nitrogen atom of another molecule
Hydrogen bonds are significant for the properties of water and biological molecules like DNA.
What does a chlorine atom do to become a chloride ion?
It tends to gain one electron
This gain of an electron results in a negatively charged ion, which is essential for forming ionic compounds.
What are the differences between ionic bonds and covalent bonds?
Ionic bonds involve transfer of electrons, while covalent bonds involve sharing of electrons
These differences affect the properties and behavior of the resulting compounds.
Describe the major subatomic particles that make up an atom.
Protons, neutrons, and electrons
Protons are positively charged, neutrons are neutral, and electrons are negatively charged.
Why do isotopes of an element have the same chemical properties?
They have the same number of electrons
The chemical properties are primarily determined by the electron configuration, which remains unchanged among isotopes.
How do the physical and chemical properties of a compound compare to those of the elements it is composed of?
They can be very different
The properties of compounds often differ significantly from the properties of the individual elements due to the nature of chemical bonding.
What does the presence of liquid water on a planet suggest?
That life may be present
What is the chemical formula for water?
H2O