Upload
angelina-taylor
View
214
Download
1
Tags:
Embed Size (px)
Citation preview
Activity 12 Major Concepts:• Graphing is used to analyze and clarify
data
• People make important personal and social decisions based on perceptions of benefits and risks (trade-offs)
Activity 14 Major Concepts:• Substances have characteristic properties,
such as density and conductivity, that are independent of the amount of the sample
• Substances are often placed in categories or groups if they react in similar ways; metal is an example of such a group
• The properties of materials determine their uses
Activity 15
Title: Families of Elements
Read B-19Problem: How can elements be grouped
based on their physical and chemical properties?
Hypothesis/Initial Thoughts:
Procedure: Read and follow the procedure on pages B-20 and B-21.
Background:• More than 2000 years ago, the Greeks
introduced the idea that there were some basic building blocks of matter, called elements
• Today scientists know that there are 90 naturally occurring elements---substances that cannot be broken down by any normal chemical means, such as heating, reacting them with acids or other chemicals, or exposing them to electrical currents.
Background:
• Each visible sample of an element is made of many billions of small particles called atoms.
• Each kind of element is made of a particular kind of atom.
• From Activity 14:– Copper– Aluminum– Iron– carbon
These 4 are elements and are among some of the first elements early scientists discovered
Background:
Element symbol (chemical symbol)
• Shown by one or two letter symbols
• A capitol letter (H, B, S, O)
OR
• A capitol and a lower case letter (Br, Si, Zn)
Physical Properties
• Metal or non-metal
• Solid, liquid or gas
• The color of most common form(s)
• The atomic mass refers to the mass of one atom (the smallest bit of each element) as based on hydrogen.– Can’t directly be weighed– Expressed as atomic mass units (amu)
Chemical Properties
• Reactivity refers to how likely the element is to interact chemically, or react, with other elements.– Oxygen is very reactive, so its reactivity is
listed as high.
• Number of hydrogen bonds– Hydrogen is the simplest element and can
form only one bond
Sort the element cards
• Form at least 3 categories
• Must have 2 similar characteristics within each category
• You might want to start with only one criterion to begin your categories
Data/Observation:
Procedure #4 (My Classification)
Group name
If needed
If needed
Common properties
Procedure #9 (Class Classification)
Family Name
Similar Properties
Elements in order of increasing atomic mass
Follow-up:• The cards in the activity show only 14 of
over 100 known elements
• Scientists have taken a similar approach to classify and organize all the elements onto a table called the Periodic Table of Elements
• The categories for the Element Family Cards are four of the accepted scientific classifications
alkali metals
alkaline earth metals
halogensnoble gases