Name _________________________________ Date ____________ Period _________ Atoms, Elements, Compounds, and Mixtures -- Notes Pages for PowerPoint Presentation Slide 1: Structure of the Atom Atoms are the ________________ into which matter can be divided and still maintain its characteristics. Atoms are the __________________ of the universe. There are ___ different kinds of atoms that occur naturally, although more are man-made. These building blocks can be ________________________ to create all of the different kinds of matter we can observe. All atoms share the _____________________. Over the years, scientists have designed ________________ ____________ for this structure. Each one was the best model at the time, but as _________________________________, the models were revised to fit it. Scientists will probably ____________ the current model as more evidence becomes available. Slide 2: Early Atomic Models The Greek scientist _______________ was the first person to say that all matter is made of atoms, but he also said that atoms are ____________________. In the early 1800’s, the English scientist ______________________ developed his ____________________________________. It said four things: (1) _____________________________________________. (2) _____________________________________________. (3) ___________________________________________________________. (4) ______________________________________________________________. In the late 1800’s, ___________________ discovered that atoms were made of smaller particles. He discovered the _____________ and devised the “____________________” model of the atom. Slide 3: Recent Atomic Models In the early 1900’s, scientists discovered the positively-charged ____________. In 1911, __________________ discovered the ______________ of the atom, where protons are located. Atoms are mostly ____________________________. Niels Bohr changed Rutherford’s model in ___________. Bohr said that electrons move around the nucleus in __________________________. Electrons can move from one energy level to another. Bohr’s model has been called the “________________” model of the atom. The current model of atomic structure is called the “________________” model. Electrons move within an energy level ________________________________, not a fixed orbit. __________________ bond with protons in the nucleus. Slide 4: Atomic Number and Mass Number All atoms of an element have the _________ number of protons, and different elements have ______________ numbers of protons in their atoms. The atomic number of an atom is the number of _____________ it has. If the atom is neutral, the atomic number is also the number of ________________. Atoms of the same element may have different numbers of _____________. Atoms with extra or missing neutrons are called _________________. An atom’s mass number is the number of ______________ plus ______________. Different isotopes of an element have different ____________ numbers. Atomic number of this neutral atom = 6. This means that it has 6 ___________ and 6 ______________. Mass number of this neutral atom is 14. This is the sum of the _____________ plus ______________. Since there are 6 protons, there must be 14 - 6 = ____ neutrons. Slide 5: Elements An element is matter that is made of only ________ kind of atom. All of the atoms of an element are _____________. There are ________ naturally occurring elements. Elements can be identified by their _____________________. Some properties are _______, _____________, _______________, _________________, __________________, ability to __________________ in water, and ability to conduct _________or ___________________. At room temperature, most elements are _______________, although a few are ________________ and some are ________________. Chemical ________________ are abbreviations for the names of elements. You can also use a chemical symbol to represent one ___________ of an element. Chemical symbols are the same all over the world, no matter what language is spoken. The first letter is _________ capitalized, and if there is a second letter it is _________ capitalized. Slide 6: Compounds The atoms of most elements are very _____________. They __________________ join together with atoms of other elements to form _____________________. The properties of compounds are ________________________than the properties of the elements that make the compound. When elements join to make compounds, they _________________ join in the same proportion. H2O is water, not HO or H3O ! Compounds are separated into __________ groups, depending on how their atoms are joined: (1) Molecular compounds are made of atoms that ____________ electrons. (2) Ionic compounds are made of atoms that ________ or ___________ electrons. Chemical ________________ represent compounds. They show the _________ and ______________ of atoms in the compound. H2O H is symbol for ____________________ O is symbol for _____________________ Subscript 2 means that there are ___ Hydrogen atoms No subscript means ____ Oxygen atom Water molecule NH3 N is symbol for _____________________ H is symbol for ___________________ No subscript means ____ Nitrogen atom Subscript 3 means there are 3 ________________ atoms Ammonia Molecule Slide 7: Mixtures Mixtures are made when there are at least ______________ different kinds of atoms that are in the same place but are ______ chemically combined. A mixture can be made with __________ proportion of ingredients, but a compound must be made in only ________ certain way. Components of a mixture _____________ their own properties, but those of a ___________________ do not. Components of a mixture are not ____________________ combined, so they can be separated by _________________ means. Slide 8: Types of Mixtures A homogeneous mixture is __________________ throughout. All parts of the mixture have the ___________ proportion of ingredients. A heterogeneous mixture is ________________________ in different parts. Different regions of this kind of mixture have ____________________ proportions of the ingredients. An ______________ is a homogeneous mixture of metals. All ________________________ are homogeneous mixtures. Homogeneous mixtures Heterogeneous mixtures 1. 1. 2. 2. 3. 3. 4. 4. 5. 5.