ECM (Elements, Compounds, and Mixtures)
This type of matter has a uniform composition and cannot be separated by physical means.
Pure substance
This symbol represents a chemical reaction taking place.
An arrow (→)
The smallest unit of matter that retains the properties of an element.
An atom
The number of electrons in the outer shell (valence electrons) determines how an atom will bond and react with other atoms.
Periods
This type of bond forms when atoms share electrons.
Covalent bond
Unlike a compound, this type of mixture can be separated by physical methods like filtering or magnetic separation.
Heterogeneous mixture
In a balanced chemical equation, this law states that atoms cannot be created or destroyed.
Law of Conservation of Mass
These are the negatively charged particles that orbit the nucleus of an atom.
Electrons
This column contains elements that are good conductors of heat and electricity.
Metals
Give an example of a common ionic compound found in table salt.
NaCl sodium chloride
Name two examples of a homogeneous mixture that an 8th grader might encounter daily.
Salt water, sweet tea, lemonade, etc.
Balance this chemical equation: H2+O2→H2O
2H2+O2→2H2O
Explain how the number of protons determines an element's identity.
The number of protons in an atom's nucleus defines its atomic number and determines which element it is.
Explain how the periodic table is organized from left to right.
Elements are arranged by increasing atomic number, with elements in the same column having similar chemical properties.
Explain how the electron configuration changes when an ionic bond forms.
Positively and negatively charged ions
Explain the difference between an element and a compound using a specific example.
An element is a pure substance made of only one type of atom (like gold), while a compound is made of two or more different elements chemically bonded (like water, H2OH2O).
Explain the difference between a reactant and a product in a chemical equation.
Reactants are the starting substances before a chemical reaction, and products are the new substances formed after the reaction.
Draw and explain the difference between an ionic and a covalent bond.
An ionic bond involves transferring electrons between atoms (like in salt), while a covalent bond shares electrons between atoms (like in water).
Describe the characteristics of elements in the noble gas group.
Noble gases are stable, non-reactive, and have a full outer electron shell.
What type of elements typically form ionic bonds? What type forms covalent bonds?
Ionic=metal and non-metal
Covalent=non-metals
Describe how you could physically separate the components of a mixture of salt, iron filings, and sand.
Use a magnet to remove iron filings, then use filtration to separate sand, and finally evaporation to collect salt.
Write a balanced equation for the rusting of iron, showing how iron reacts with oxygen.
4Fe+3O2→2Fe2O3
Describe how the arrangement of electrons in an atom's outer shell affects its chemical behavior.
The number of electrons in the outer shell (valence electrons) determines how an atom will bond and react with other atoms.
Explain how the position of an element on the periodic table can predict its reactivity and bonding behavior.
Elements closer to the left or right sides of the periodic table tend to be more reactive, while those in the middle are less reactive.
Which of the following compounds is most likely to form an ionic bond: NaCl, H2O, CO2? Explain your reasoning.
NaCl because sodium is a metal and chlorine is a non-metal