Science - 2018-19
PS.4 - Periodic Table
The student will investigate and understand the organization and use of the periodic table of elements to obtain information. Key concepts include
a) symbols, atomic number, atomic mass, chemical families (groups), and periods;
b) classification of elements as metals, metalloids, and nonmetals; and
c) formation of compounds through ionic and covalent bonding.
- The periodic table provides information about the atoms of an element.
- Periodic trends of atoms allow for the prediction of physical and chemical properties
- Chemical bonding occurs as a result of attractive forces between particles.
I can identify elements in a compound based on their symbols.
- I can describe the compounds in my food and drinks.
UNDERSTANDING THE STANDARD
- There are more than 110 known elements. No element with an atomic number greater than 92 is found naturally in measurable quantities on Earth. The remaining elements are artificially produced in a laboratory setting. Elements combine in many ways to produce compounds that make up all other substances on Earth.
- The periodic table of elements is a tool used to organize information about the elements. Each box in the periodic table contains information about the structure of an element.
- An atom’s identity is directly related to the number of protons in its nucleus. This is the basis for the arrangement of atoms on the periodic table of elements.
- The vertical columns in the table are called groups or families. The horizontal rows are called periods.
- Elements in the same column (family) of the periodic table contain the same number of electrons in their outer energy levels. This gives rise to their similar properties and is the basis of periodicity — the repetitive pattern of properties such as boiling point across periods on the table.
- The periodic table of elements is an arrangement of elements according to atomic number and properties. The information can be used to predict chemical reactivity. The boxes for all of the elements are arranged in increasing order of atomic number. The elements have an increasing nonmetallic character as one reads from left to right across the table. Along the stair-step line are the metalloids, which have properties of both metals and nonmetals.
- The nonmetals are located to the right of the stair-step line on the periodic table.
- Metals tend to lose electrons in chemical reactions, forming positive ions. Nonmetals tend to gain electrons in chemical reactions, forming negative ions.
- Gaining or losing electrons makes an atom an ion.
- Gaining or losing neutrons makes an atom an isotope. However, gaining or losing a proton makes an atom into a completely different element.
- Atoms react to form chemically stable substances that are held together by chemical bonds and are represented by chemical formulas. To become chemically stable, atoms gain, lose, or share electrons.
- Compounds are formed when elements react chemically. When a metallic element reacts with a nonmetallic element, their atoms gain and lose electrons respectively, forming ionic bonds. Generally, when two nonmetals react, atoms share electrons, forming covalent (molecular) bonds.
In order to meet this standard, it is expected that students will
a) use the periodic table to obtain the following information about the atom of an element:
- atomic number
- atomic mass
- state of matter at room temperature
- number of outer energy level (valence) electrons.
describe the organization of the periodic table in terms of
- atomic number
- metals, metalloids, and nonmetals
- groups/families vs. periods.
recognize that an atom’s identity is related to the number of protons in its nucleus.
b) categorize a given element as metal, nonmetal, or metalloid.
c) given a chemical formula of a compound, identify the elements and the number of atoms of each that comprise the compound.
recognize that the number of electrons in the outermost energy level determines an element’s chemical properties or chemical reactivity.
describe the difference between ionic and covalent bonding.predict what kind of bond (ionic or covalent) will likely form when metals and nonmetals are chemically combined.
periodic table of elements, periods, ion, isotope, metals, nonmetals, compound, atomic number, atomic mass, ionic bond, covalent bond, metalloids, element, valence electrons, family