Chapter 2 Test Review Flashcards
Elements of CHONPS?
Carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur
4 elements that make up 96% of living matter
Carbon, hydrogen, oxygen, nitrogen
Example of a trace element that all organisms need
Iron
Example of a trace element that all vertebrates need
Iodine
Mass number?
Protons+neutrons= mass number
Atomic number?
Protons= electrons= atomic number
How can two atoms be isotopes?
Isotopes are different forms of an element
Differ in neutrons and mass
Number of electrons in first valence shell
2
Number of electrons in second valence shell
8
Number of electrons in third valence shell
18
When is a covalent bond polar?
When one atom is more electronegative
The electrons are not shared equally
Why are water molecules attracted to each other?
Hydrogen bonds attract water molecules to each other
Remember
Elements are in their purest form
They cannot be broken down
What makes up the nucleus of an atom?
Protons and neutrons
Where are electrons?
Electron cloud/ shells
Protons?
Positive
1 dalton
Determine element
Neutrons?
Neutral
1 dalton
Determine isotope
Electrons?
Negative
Weigh almost nothing
Determine chemical behavior
Where is potential energy greater in an atom?
Farther from the nucleus
Radioactive isotopes?
Nucleus decays spontaneously
Gives off particles and energy
When are atoms unreactive?
They have a full valence shell
What does chemical behavior of an atom depend on?
Number of electrons in the outermost shell
Remember?(?)
Electrons in a shell have a characteristic energy level
Orbitals?
Three-dimensional space with specific shapes (electron shells)
When do chemical bonds form?
When atoms interact and complete their valence shells
When do covalent bonds form?
Pairs of electrons are shared
When is an ionic bond formed?
When electrons are transferred
When is chemical equilibrium reached?
When forward and reverse reaction rates are equal
Concentration of reactants and products are equal
Smallest unit of matter that still retains the properties of an element?
Atom
More electronegativity=
Stronger pull
Remember!!!
In a chemical reaction, the reactants and products will never dis/appear
Atom in reactants are in products
