Chemistry Strand Review - Atoms and Compounds

A characteristic that describes a substance's ability to undergo changes that transform it into a different substance. For example, flammability, reactivity with acid, or oxidation (rusting).

A characteristic that can be observed or measured without changing the substance's composition. For example, color, texture, boiling point, density, or mass.

The number of protons in the nucleus of an atom, which determines the element's identity. For example, carbon has an atomic number of 6.

The sum of protons and neutrons in an atom's nucleus. For example, carbon-12 has a mass number of 12 (6 protons + 6 neutrons).

Highly reactive metals, especially with water. For example, sodium (Na) and potassium (K).

Elements that are solid at room temperature. For example, iron (Fe) and gold (Au).

Elements that are liquid at room temperature. For example, mercury (Hg) and bromine (Br).

Elements that are gaseous at room temperature. For example, oxygen (O₂) and nitrogen (N₂).

One or two-letter abbreviations representing elements on the periodic table. The first letter is always capitalized, the second (if any) is lowercase.

The number of valence electrons (outermost shell electrons) of elements in a group.

The number of electron shells in the atom of elements in a period.

Electrons in the outermost shell of an atom, determining how an atom bonds with others.

Atoms are most stable with 8 electrons in their outer shell.

Good conductors of heat and electricity, malleable, ductile, solid at room temperature (except mercury).

Poor conductors of heat and electricity, brittle (when solid), often gases at room temperature.

Have properties of both metals and nonmetals, semiconductors of electricity.

The mass per unit volume of a substance. Formula: Density = Mass/Volume

The Modern Periodic Table arranges elements by increasing atomic number (number of protons). It organizes elements into periods (horizontal rows) and groups (vertical columns) based on shared properties, especially the number of valence electrons.

Highly reactive, especially with water.

Reactive, but less so than alkali metals.

Very reactive non-metals, form salts with metals.

Inert gases, non-reactive due to full electron shells.

The number of valence electrons determines the placement of an element in a specific group.

A relationship where one organism benefits while the other is harmed.

Short-term atmospheric conditions at a specific time and place.

Long-term patterns of weather in a specific region.

Gases like CO₂ that trap heat in the Earth's atmosphere.

The process where greenhouse gases trap heat, warming the Earth.

Energy sources that cannot be replenished easily, like coal and oil.

Energy sources that can be replenished naturally, like solar and wind.

Objects with the same charge repel, opposite charges attract.

A force that attracts or repels objects based on their electric charge.

The opposition to the flow of electric current.

A material that allows electrons to flow easily through it.

A material that resists the flow of electrons.

The process of charging a neutral object by bringing a charged object close to it, causing a redistribution of charges in the neutral object.

The measure of the opposition to the flow of electric current in a conductor.

The difference in electrical potential between two points in a circuit.

The rate of flow of electric charge.

A circuit where all components are connected in a single path.

A circuit where components are connected in multiple paths.

A device that provides a potential difference (voltage) in a circuit.

A device that controls the flow of current in a circuit.

A component in a circuit that converts electrical energy into another form of energy (e.g., light, heat, motion).

A component in a circuit that provides resistance to the flow of current. Used to control the flow of electricity.

A device that converts electrical energy into light energy.

A device that converts electrical energy into mechanical energy.

The layer of gases surrounding the Earth, composed primarily of nitrogen, oxygen, and trace gases.

All the water on Earth, including oceans, lakes, rivers, glaciers, and groundwater.

The global sum of all ecosystems, including all living organisms and their interactions with the environment.

The Earth's outermost layer, including the crust and upper mantle. Landforms like mountains, valleys, and tectonic plates are part of it.

The process by which liquid water turns into water vapor and rises into the atmosphere.

The process where water vapor in the atmosphere cools and changes back into liquid water or ice crystals.

Water falling back to Earth from the atmosphere in different forms like rain, snow, hail, and sleet.

The process where water soaks into the ground, replenishing underground water sources.

The flow of water across the land surface, eventually reaching lakes, rivers, and oceans.

The movement of carbon between abiotic and biotic parts of an ecosystem, including processes like photosynthesis, respiration, and decomposition.

The process where producers capture sunlight and convert it into glucose, a form of energy for later use. Plants use this process.

The process where organisms use glucose to release energy, called ATP. This process releases CO2 back into the atmosphere.

The process where microorganisms in the soil convert atmospheric nitrogen into nitrates, which are usable by plants.

The process where nitrates in the soil are converted back into nitrogen gas in the atmosphere.

A method of growing crops in vertically stacked layers, often in controlled indoor environments.

A substance that contains carbon atoms bonded to hydrogen atoms (C-H bonds), typically part of a larger, more complex molecule.

A substance that does not contain carbon bonded to hydrogen atoms (C-H bonds).

A linear sequence of organisms where energy is passed from one to the next through feeding.

A complex network of interconnected food chains showing various feeding relationships in an ecosystem.

The position of organisms in a food chain, such as producers, primary consumers, secondary consumers, and decomposers.

An organism that makes its own food, usually through photosynthesis (e.g., plants).

An organism that obtains energy by eating other organisms.

An organism that breaks down dead organisms and organic waste, recycling nutrients into the ecosystem.

Eat plants.

Eat both plants and animals.

Eat other animals.

Eat dead organisms.

A group of individuals of the same species.

All species interacting in a given area.

Factors that limit the growth of a population.

Non-living environmental factors like temperature, water, sunlight, and soil nutrients.

Living factors like competition, predation, disease, and food availability.

Factors that depend on the population density and have a stronger effect as the population increases.

Factors that affect populations regardless of their density, often related to environmental conditions.

The maximum reproductive capacity of an organism under optimal environmental conditions, assuming no limiting factors.

The length of time during which an organism can reproduce, meaning it can produce offspring.

The variety and variability of life forms within an ecosystem, including species, genes, and ecosystems.

The large-scale clearing of forests for purposes like agriculture, logging, or urban development.

The release of harmful substances into the environment, affecting air, water, and soil.

Long-term changes in temperature, weather patterns, and sea levels caused by human activities, such as burning fossil fuels.

The accumulation of a toxic substance within an organism over time, occurring when the substance is absorbed faster than it is eliminated.

The increase in concentration of a toxic substance as it moves up the food chain, with higher predators accumulating more toxins from consuming contaminated prey.

The buildup of electric charge on the surface of an object, caused by an imbalance of electrons.

The flow of electric charge through a conductor, usually in a circuit, measured in amperes (A).

An object becomes positively charged when it loses electrons. Since electrons are negatively charged, the loss of electrons leaves the object with a net positive charge.

An object becomes negatively charged when it gains electrons. The addition of negatively charged electrons causes the object to have a net negative charge.

Objects with the same type of charge (either both positive or both negative) will repel each other.

Objects with opposite charges (one positive and one negative) will attract each other.

A neutral object will be attracted to a charged object because the charges in the neutral object rearrange to create a temporary attraction.

The movement of electrons is responsible for static charges on objects. Electrons have a negative charge, and their transfer between objects causes them to become positively or negatively charged.

Charging by friction involves rubbing two objects together, causing electrons to transfer from one object to another.

An atom or molecule that has gained or lost one or more electrons, resulting in a charged particle. For example, Na⁺ (sodium ion) or Cl⁻ (chloride ion).

A substance made up of two or more non-metal atoms bonded together by covalent bonds. For example, H₂O (water) or CO₂ (carbon dioxide).

A change in the state or appearance of a substance without altering its chemical composition. For example, melting ice or boiling water.

A chemical change is a process that results in the formation of new substances with different properties. Here are 5 key points:

1. Formation of a new substance: A chemical reaction produces new substances with different properties. For example, burning wood creates ash and gases.

2. Change in color: A color change often indicates a chemical reaction (e.g., rust forming).

3. Release or absorption of energy: Energy (heat, light, or sound) may be released (exothermic reaction) or absorbed (endothermic reaction). For example, burning fuel releases heat.

4. Formation of gas: The appearance of bubbles or gas indicates a reaction (e.g., vinegar reacting with baking soda).

5. Formation of a precipitate: A solid may form when two solutions are mixed (e.g., silver chloride precipitating from silver nitrate and sodium chloride).

Magnesium loses two electrons to become Mg²⁺ (magnesium ion). Chlorine gains one electron to become Cl⁻ (chloride ion).

Magnesium chloride (MgCl₂).

MgCl₂.

A pure substance is made up of only one type of particle (atoms or molecules) and has a consistent composition throughout. It cannot be separated into other substances by physical methods. For example, water (H₂O), oxygen (O₂), or gold (Au).

The components of a heterogeneous mixture are not uniformly distributed, and different parts of the mixture can be distinguished. For example, salad, gravel, or oil and water.

A mixture consists of two or more substances (elements or compounds) physically combined. These substances retain their individual properties. Mixtures can be separated by physical methods like filtration, distillation, or magnetism. For example, saltwater, air, or salad.

A homogeneous mixture is a mixture where the components are evenly distributed throughout the mixture, and the composition is uniform. For example, saltwater, air, or a well-mixed solution of sugar in water.

All Matter is Made of Tiny Particles:

Everything in the universe is composed of particles, which can be atoms, ions, or molecules. This basic unit is the foundation of the particle theory.

Particles are Always in Motion:

The particles of matter are never stationary. Their motion depends on the state of matter (solid, liquid, gas). In solids, the particles vibrate in place, while in liquids and gases, they move more freely.

Particles are Attracted to Each Other:

There are forces of attraction between particles that vary in strength depending on the type of matter and its state. For example, in solids, the attraction is strong, keeping particles close together.

There is Space Between the Particles:

In solids, the particles are tightly packed, while in liquids and gases, the particles are more spread out.

Temperature Affects Particle Motion:

The higher the temperature, the faster the particles move. This is why solids melt into liquids and liquids boil into gases when heated. The movement of particles dictates the states of matter (solid, liquid, gas). This is why you can see the effects of particle motion in the everyday world: like boiling water or an ice cube melting.