2.1, 2.5 Flashcards
Distinguish between the two broad types of matter
substance - matter with a fixed composition
mixture - two or more substances that are physically combined with a variable composition
what can substances be further subdivided into?
elements and compounds
define an element
the simplest type of matter with unique physical and chemical properties
4 properties of an element
- consists of only one kind of atom
- each element is unique because the properties of its atoms are unique
- in nature, most elements exist as populations of atoms
- several elements occur in molecular form
define a compound
consists of two or more different elements bonded chemically with a fixed number of atoms of each element
how do mixtures differ from compounds?
- components of a mixture can vary in their parts by mass
- a mixture retains many of the properties of its components
- mixtures can be separated into their components by physical changes; chemical changes are not needed
compare heterogeneous mixtures and homogeneous mixtures
heterogeneous:
- one or more visible boundaries among the components
- the composition is not uniform throughout the mixture, but rather varies from one region of the mixture to another
homogeneous:
- has no visible boundaries
- has a uniform composition
- components are uniformly intermingled on a molecular level
draw a flow diagram for the different types of matter
p.46
where does staircase on the periodic table lie?
boron/aluminium -> silicon
metals
shiny solids at room temp (except mercury), conduct heat and electricity, malleable, ductile
nonmetals
gases or dull brittle solids (except bromine), conduct heat and electricity poorly
metalloids
B, Si, Ge, As, Sb, Te
have properties between those of metals and nonmetals
lanthanides
top row
actinides
bottom row
elements in a group have —— chemical properties; elements in a period have ——- chemical properties
similar; different
