Periodic Table
This chart arranges elements by increasing atomic number and groups elements with similar properties
Periodic Table
Give one example of a physical change students can easily observe in class.
Example: Cutting paper, melting ice
Name one property that most metals share (appearance or physical behavior)
Example: shiny, good conductors, malleable
Define a homogenous mixture in student-friendly words and give one example
homogenous; uniform mixture.
salt water, sugar water, coolaid
What is an element? Five a 1-2 word example from everyday life.
Element: single type of atom, e.g., gold
Name the island-like on the periodic table that separates metals from nonmetals.
Zigzag line
List two pieces of evidence that indicate a chemical change has occurred.
Evidence: gas/bubbles, temperature changes, precipitate, unexpected color change, light/sound
Give one property that distinguishes nonmetals from metals
Nonmetals are poor conductors and often gases or brittle solids
Define a heterogenous mixture and give on classroom example.
Heterogenous: not uniform
What is a molecule? Give a example.
Molecule; two or more atoms bonded, e.g., water (H2O).
Explain why elements in the same column(group) often show similar chemical behavior
Elements in a group have similar valence electron arrangements so similar properties
A student melts ice, boils water, and dissolves sugar in water. Which of these are physical changes. Explain briefly
All are physical: melting and boiling are state changes; dissolving is physical mixing
Metalloids have characteristics of both metals and nonmetals. List two physical properties that show this mixed behavior.
Shiny like metals but brittle like nonmetals; semiconducting conductivity.
Salt dissolved in water forms a single uniform phase. Is this homogenous or heterogenous? Explain why.
Homogenous - Salt fully dissolves , appears the same everywhere.
Explain one key difference between an element and a molecule.
Element is one kind of atom; molecule is two or more atoms chemically bonded.
Identify were you would find metalloids on the periodic table and give one example of how they are used in technology
Along zigzag line between metals/nonmetals; used as semiconductors in computers/phones
Describe how a temperature change can be evidence of a chemical reaction; give one classroom example that would show this.
Temperature changes shows energy released or absorbed; example
Mercury is unusual among metals, Explain why based on state of matter at room temperature.
Mercury is liquid at room temperature, unlike most metals
A mixtures shows visible particles that settle after a few minutes. Identify the type of mixture and evidence you see.
Heterogenous- visible particles settle, so not uniform
Oxygen that living things breathe is written O2. Is O2 an element or a molecule? Explain.
OX is a molecule made of tow oxygen atoms; oxygen as O2 is a molecule of one element.
Rare earth elements include those with atomic numbers 57-71. Describe two modern uses for these elemensts
Uses: smartphone/Tb screens, batteries in hybrid/electric cars
A reaction between two clear liquids produces bubbles and a yellow color unexpectedly. Explain why this is evidence of a chemical change, using the concept of new substances.
Bubbles + unexpected color indicate new substances formed - chemical change
Only three elements are strongly magnetic at room temperature. Name one and say whether it is a metal, nonmetal, or metalloid.
Iron(Fe)- a metal(also magnetic)
Nickel(N)- a metal
Cobalt(Co)- a metal
Describe how you could test whether a mixture of sand and salt is homogenous or heterogenous using simple classroom steps.
Add water; sand will not dissolve (heterogenous) while salt will dissolve (homogenous solution); filter to separate sand from salt water
Describe a classroom demonstration (simple and safe) that shows the difference between a single element sample and a compound (molecule) sample forming a new substance.
Demo: show a sample of copper metal (element) and then mix hydrogen and oxygen in a safe demo that produces water (compound) -