Atoms and elements
What is the smallest unit of matter?
atom
what does the periodic table organize?
elements by their atomic number
what is the difference between an element and a compound?
a element is made of one kind of atom , a compound is made of two or more elements.
what is physical change?
change in form or appearance without making a new substance.
what should you always wear to protect your eyes in the lab?
goggles
what are three subatomic particles?
protons,neutrons and electrons.
what is the symbol for sodium?
Na
is salt(NaCl)an element or a compound?
compound
what is chemical change?
change that forms a new substance
What should you do if a chemical spills on your skin?
rinse it immediately and tell the teacher
what is the centre of an atom called?
nucleus
which group on the periodic table contains carbon?
Group 14
what is a mixture?
combination of two or more substances not chemically bonded
is melting ice a chemical or physical change?
physical
what charge does a proton have?
positive electric charge
what do we cal a horizontal row on the periodic table?
a period
what is a chemical formula for water?
H2O
Give one sign of a chemical change?
color change,temperture change,gas or light formation
what is the atomic number of an element?
number of protons in the nucleus
what do we call a vertical colum on the periodic table?
a group or family
is air a compound or a mixture?
mixture