Atoms
Name the three main particles in an atom.
Protons
Neutrons
Electrons
what is a compund
a pure chemical substance made of two or more different elements chemically bonded together in a fixed ratio
Define an element
Pure substance with only one type of atom
Why is oxygen written as O and not Ox?
Standardized symbols (usually 1–2 letters from Latin/English)
What does atomic mass represent?
Average mass of isotopes
Why are atoms electrically neutral?
Equal number of protons and electrons
What type of bond is in NaCl?
Ionic bond
which group of elements is the least reactive?
Noble gases
What is the symbol for sodium?
Na
why is atomic mass sometimes a decimal?
because of isotopes
What happens when an atom loses an electron?
It becomes positive
How many oxygen atoms are in CO₂?
2
What do elements in the same group have in common?
ame number of outer (valence) electrons
What is the symbol for oxygen?
O
is atomic mass a small number or big number?
Big number
Where are protons found?
in the nucleus
What is H₂O called?
Water
Why are elements in the same group similar?
hey have the same number of valence (outer) electrons
What does CO₂ tell you about the atoms?
1 carbon atom and 2 oxygen atoms
Why is atomic mass usually a decimal?
Because it is the average of different isotopes
Is atoms the smallest cell
yes
what is an Compound
Pure substance made up of atoms of two or more elements, strongly joined together.
What is the definition of Element
Substance that all other materials are made of and which contain only one type of atom. they cannot be broken down into other substances.
what is an chemical symbol
A one or two letter code for an element that is used by scientist in all countries
what is atomic mass
The average mass of an element accounting for the different forms in which it is found