Biology Chapter 2 Flashcards
What is the difference between an element and a compound
An element is substance that cannot be broken down into other substances by ordinary chemical procedures
And a Compound is made up of two or more elements in a fixed ratio
Identify the four elements that make up 96% of living matter
C, H, O, N Carbon, hydrogen, oxygen, nitrogen
Are Trace elements essential?
Yes, trace elements are essential but needed in small amounts
The nucleus of each atom has a characteristic number of protons and neutrons.. the protons are_______ charged and the neutrons are _________charged.
The nucleus of each atom has a characteristic number of protons, the PROTONS=POSITIVE, NEUTRONS=ELECTRICALLY NEUTRAL
Inside an atom there is a __________ and inside of a nucles there is ___________
Inside an atom there is a nucleus and inside of a nucles there is protons and neutrons
The Atomic number represents…..
The Atomic number represents the number of protons in an atoms nucleus
The mass number represents the number of particles in the nucleus….the number of particles in the nucleus is________+________
The mass number represents the number of particles in the nucleus….the number of particles in the nucleus is Protons +Neutrons
What is an Isotope? In one does the proton number ever change?
Isotopes are Elements whose ATOMS VERY IN NUETRON NUMBER AND MASS NUMBER, NO the number of protons Never changes Just the number of neutrons.
Is an isotope radioactive?
An isotope may or may not be readioactive.
How do you calculate the number or Number of Neutrons from the mass number and atomic number? Explain..
Mass Number - Atomic Number=neutrons
Mass number is both pro and neu, atomic is just pro, subtract the pro from the mass and see what is left.
What are Valence Electrons? What do they do?
The number of electrons in an atom’s outer shell, and Largerly determine its chemical properties.
The chemical properties of an atom depend mostly on ___________________________________
The chemical properties of an atom depend mostly on the number of electrons in its outermost electron shell
When is an atom most stable? Are the electrons present ever different?
An atom is most stable when it has a full outermost shell. Yes, two electrons for small atoms such as hydrogen and eight electrons for
larger atoms such as carbon or chlorine.
How do atoms complete their Outer shell? WHAT DO THESE INTERACRTIONS DO?
Atoms complete their outer shell by TRANSFERING OR SHARING ELECTRONS . THESE INTERACTIONS CREATE CHEMICAL BONDS
Which atoms are the most chemically reactive?
Atoms which need to give up or acquire only one or two electrons to complete their valence shells are the most chemically reactive
(EX. Na+1 , Cl-1). (Sodium and chlorine )
What are the 5 types of Chemical Bonds?
-Covalent bonds
-Nonpolar covalent bonds
-Polar covalent bonds
-Ionic bonds
-Hydrogen bonds
What do Covalent Bonds involve? What does it form?
What is an example?
Covalent bonds involve sharing a pair of outer-shell electrons between two atoms.
It forms a Molecule.
EXAMPLE: Two hydrogen atoms each have 1 electron but need 2 to fill their shells. By sharing electrons, they form a covalent bond.
What is a molecule defined as?
Two or more atoms held together by covalent bonds
What causes an ionic bond?
Ionic bonds result from the attraction between oppositely charged ions causing one electron to be transfered to another atom
What is a hydrogen bond?
A hydrogen bond is a weak attraction between the positive hydrogen atom of one molecule and the negative atom (usually oxygen) of another molecule.
Why are hydrogen bonds important?
Hydrogen bonds are crucial for life because they help proteins fold correctly and hold the DNA strands together.
What are Van Der Waals interactions?
Van Der Waals interactions are weak attractions between molecules or parts of molecules caused by temporary charge fluctuations due to the movement of electrons.
Why are Van Der Waals interactions important?
Though weak, Van Der Waals interactions help stabilize the 3-D structure of molecules by adding a small but important amount of attraction, especially when there are many of them.
How does a molecule’s shape influence its biological function?
A molecule’s shape determines how it interacts with other molecules. For example, a neurotransmitter’s shape allows it to fit into a receptor on a neuron, like a “lock-and-key,” enabling it to transmit a signal. These interactions are usually weak (hydrogen bonds, ionic, or Van Der Waals forces).
