Chapter 2 Flashcards
The number of protons in the nucleus of an atom is called the ______
Atomic number
At the center of an atom the positive charged subatomic particles is called a ______
Proton (purple) +
Positive charge
At the center of an atom the not charged subatomic particle is called the _______
Neutron (no charge) blank
The orbiting cloud of a third kind of subatomic particle with a negative charge is the ________
Electron (yellow) -
Negative charge
What charge does a Neutron have?
None, no charge
What charge does a Proton have?
A positive charge
What charge does a electron have?
Negative charge
What is an electrically neutral atom?
When the electrons negative charge balances the protons positive charge (+,—)
The number of protons and neutrons in the nucleus of an atom is called the _______
Mass number
A carbon atom that has six protons and six neutrons has a mass number of ____
12
Atoms where the number of electrons does not equal the amount of protons because they have gained or lost one or more electrons are called _____
Ions
A group of atoms held together by energy
Molecule
The energy force holding two atoms together is called a ________
Chemical bond
What are the three principal kinds of chemical bonds?
Ionic bonds
Hydrogen bonds
Covalent bonds
Positively charged ions are called
Cation
Negatively charged ions are called
Anions
Atoms that have the same number of protons but different numbers of neutrons are called
Isotopes
What’s the difference between an Anion and a Cation Ion?
When a atom looses an electron and it does not equal the number of protons in the nucleus it becomes an ion. Then if it’s one electron short it’s a Cation. If an atom Gaines an extra electron from another atom it’s an anion.
What is a molecule
A group of atoms held together by Energy, energy is glue
Isotopes of an atom have the same ______ number but different ______ number.
Atomic, mass
The energy or force holding two atoms together is called a
Chemical bond
What do chemical bonds determine
The shapes of the large biological molecules
Chemical bonds that form when atoms are attracted to each other by opposite electrical charges.
Ionic bonds
What are two key properties of ionic bonds?
They are strong, they are non directional.
Strong chemical bond formed betweeen two atoms when they share electrons.
Covalent bonds
Molecular magnet, with positive and negative ends or “poles” one portion of the molecule attracts electrons more strongly that another portion is called
Polar molecules
Molecules that don’t exhibit a large difference in electronegatives of its atom like the carbon hydrogen bonds of methane are
Nonpolar Molecules
Two key properties of covalent bonds
They are strong, sharing lots of energy
They are very directional- bonds form between two specific (intentional) atoms
Bonds that accur when the positive end of one polar molecule is attracted to the negative end of another like magnets
Hydrogen bond
Electrons equally shared between atoms
Non polar covalent bonds
Forms when electronegativity difference between atoms is very large. Loosing an electron would benefit one atom more than sharing
Ionic bond
Two atoms are very close together, attraction is WEAK and disappears if they move a little.
Can der waals forces
Hydrogen bonds require considerable heat before they break, minimizing temperature changes.
Heat storage
Water molecules in an ice crystal are spaced relatively far apart because of hydrogen bonding
Ice formation
Many hydrogen bonds must be broken for water to evaporate
High heat of vaporization
Hydrogen bonds hold molecules of water together
Cohesion
Water molecules are attracted to ions and polar compounds.
High polarity
Hydrophilic
Hydro (water) Philic (loving) describing polar molecules, which form hydrogen bonds with water and are soluble in water
Difference between ion and polar molecule
Ions are a full charge due to loss or gain (positive or negative) Polar molecules are partial (slightly more positive or negative) just kinda pulling them their direction
No polar compounds shrink from contact with water. Do not form hydrogen bonds with water and are not soluble in water.
Hydrophobic
Positive ion (H+)
Hydrogen
A substance that takes up or releases hydrogen ions (H+) to maintain the pH within a certain range
A buffer
Negative ion (OH-)
Hydroxide
Any substance that dissociates in water to increase the concentration of H+ is called an
Acid
Acidic solutions have pH values below
7
Any substance that combines with H+ when dissolved in water is called a
Base
The subatomic particles involved in chemical reactions are the
Electrons
Moving an electron away from the positively charged nucleus of an atom _______ while moving an electron toward the nucleus _______
Requires an input of energy, results in an electron with less potential energy
The spherical orbital located in the first electron shell of all atoms is the ______ orbital while the _______ orbital is shaped like a dumbbell and present in all atoms with more than one electron shell.
S, s,,,,, P, p
What is the function of electrons in chemical reactions
They interact with the electrons of other atoms
Cells must regulate pH to prevent detrimental changes to the ______ that govern metabolism
Protein(s)
The energy levels of electrons in orbit around a nucleus within an atom are referred to as electron _______
Shells
Contained in the first energy level of any atom
One orbital
Contained in the second electron energy level
Four orbitals
Maximum number of electrons contained in one p or one s orbital
2 electrons
Maximum number of electrons contained in the second electron shell
8 electrons
A solutions _____ is equal to the negative log of its hydrogen ion concentration.
pH
Because water has a high heat of vaporization, a considerable amount of heat energy is _______
Removed when water evaporates
