Review for unit test Flashcards
What are the two main groups of matter?
Pure substances and mixtures
What are elements?
Fundamental substances listed in the periodic table, each consisting of a specific type of atom.
What are compounds?
Formed from groups of different atoms bonded together.
What are homogeneous mixtures?
Mixtures with one visible component, such as saltwater.
What are heterogeneous mixtures?
Mixtures with two or more visible parts, such as salad.
What are physical properties?
Characteristics that can be observed directly, such as color, luster, malleability, ductility, hardness, boiling point, and melting point.
What are chemical properties?
Describe how a material reacts with other substances, such as wood being combustible or sodium reacting violently with water.
What are physical changes?
Occur when a material changes shape or form without producing new materials, such as ice melting or sugar dissolving in water.
What are chemical changes?
Occur when a material undergoes a reaction that produces a new substance, such as the rusting of iron.
What are the three subatomic particles?
Protons, neutrons, and electrons.
Where are protons and neutrons located in an atom?
In the nucleus.
Where are electrons located in an atom?
Outside the nucleus.
What is the atomic number?
The number of protons in an atom.
What is the mass number?
The sum of protons and neutrons in an atom.
What are valence electrons?
Electrons in the outermost shell of an atom.
What is an ion?
A charged atom formed by gaining or losing electrons.
What is a cation?
A positively charged ion formed by losing electrons.
What is an anion?
A negatively charged ion formed by gaining electrons.
Why do atoms form ions?
To achieve a stable electron configuration, often by having a full outer shell.
What is hyponatremia?
condition caused by low sodium levels in the blood, often due to excessive water consumption.
What are some essential ions in the body?
Calcium, phosphorus, and iron ions.
How do alkali metals form ions?
By losing one electron to form a +1 cation.
How do halogens form ions?
By gaining one electron to form a -1 anion.
What are ions?
Charged atoms formed by gaining or losing electrons.
What are the two main types of ions?
Cations (positive) and anions (negative).
How do metals typically form ions?
By losing electrons to form cations.
How do nonmetals typically form ions?
By gaining electrons to form anions.
What is ionic bonding?
The attraction between positively charged cations and negatively charged anions.
Why do atoms form ions?
To achieve a stable electron configuration, often by having a full outer shell.
What is the role of calcium ions in the body?
Calcium ions are important for neurotransmitter function, enzyme activity, muscle contraction, and bone formation.
What is an ionic bond?
A bond formed by the transfer of electrons between a metal and a nonmetal.
What is the role of magnesium ions in the body?
Magnesium ions are essential for ATP function, DNA and RNA formation.
What is a covalent bond?
A bond formed by the sharing of electrons between two nonmetals.
What is a Lewis dot diagram?
A diagram that shows the valence electrons of an atom as dots.
What is electronegativity?
Electronegativity is a measure of an atom’s ability to attract electrons.
How can you tell if a bond is ionic or covalent?
Ionic bonds typically form between a metal and a nonmetal, while covalent bonds form between two nonmetals. You can also look at the electronegativity difference between the atoms.
What is a chemical formula?
A representation of a molecule or compound that shows the types and numbers of atoms present.
Formula of water??
H2O
Formula of Carbon dioxide??
CO2
Formula of sodium chloride??
NaCl
Ionic Compounds
Strong electrostatic forces, high melting/boiling points, hard/brittle, conduct electricity in solution
Molecular Compounds
Weak intermolecular forces, low melting/boiling points, soft/flexible, poor conductors of electricity
steps of writing chemical formulas
identify cation and anion, balance charges, write formula
Naming Ionic Compounds
Write cation name, write anion name (-ide for nonmetals), combine names
Multivalent Metals
Use Roman numerals to indicate charge (e.g., Fe²⁺ is iron(II))
Covalent Bonding
Sharing of electrons between nonmetals
Lewis Dot Structures
Represent valence electrons as dots around the element symbol
Law of Conservation of Mass
Matter cannot be created or destroyed, total mass of reactants = total mass of products
Counting Atoms in Chemical Formulas
Use subscripts to determine the number of atoms of each element
Balancing Chemical Equations
Adjust coefficients to equalize the number of atoms of each element on both sides
Decomposition Reaction
AB → A + B
Synthesis Reaction
A + B → AB
Single-Replacement Reaction
A + BC → AC + B
Double-Replacement Reaction
AB + CD → AD + CB
Combustion Reaction
Fuel + O₂ → CO₂ + H₂O + energy
Acids
Sour taste, corrosive, turns blue litmus red
Bases
Bitter taste, slippery, turns red litmus blue
Neutralization Reaction
Acid + Base → Salt + Water
rules for naming binary acids
Hydro + nonmetal stem + ic acid (e.g., HCl: hydrochloric acid).
rules for naming oxyacids
Nonmetal oxide + water. If polyatomic ion ends in -ate, acid ends in -ic acid; if -ite, acid ends in -ous acid (e.g., H₂SO₄: sulfuric acid).
pH Scale
7 is neutral, <7 is acidic, >7 is basic
