All atoms of the same element have the same number of protons Mass number (A): equal to the sum of the number of protons and neutrons for an atom
Atoms ? The study of chemistry begins with the basic unit of matter, the atom ? The Greek philosopher Democritus called the smallest fragment of matter
Starting with atoms it progresses to elements, molecules and compounds It shows how a substance can be simply represented by a chemical formula made up of both
This chapter will describe some of the fundamental chemical principles Chemical symbols are used to represent atoms and elements
The atoms of these elements are present in the compound in simple whole number ratios, i e , 2 hydrogen atoms for every 1 oxygen atom in water 3 Chemical
We observe energy through its effects on matter Matter is composed of atoms An atom is the smallest particle into which an element can be divided and still
only one type of atom (therefore, an atom is the smallest part of an element) ? 25 of the 92 naturally occurring elements are essential to life ? The 5
PROPERTIES OF MATTER 11 Chemical properties of the atom 12 Physical properties of matter 13 The four fundamental interactions 15 THE ATOMIC NUCLEUS,
The Atom Science >> Chemistry for Kids The atom is the basic building block for all matter in the an atom are electrons, protons, and neutrons
elements are essential to life ➢ The 5 elements carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur are found in all living things
Mass number (A): equal to the sum of the number of protons and neutrons for an atom Atomic mass unit (amu) is 1/12 the mass of 12C (1 660 × 10-27 kg)
30 CHEMISTRY Table 2 1 Properties of Fundamental Particles atomic models were proposed to explain the distributions of these charged particles in an atom
physical or chemical means Represented by a chemical symbol Atom – Smallest particle into which an element can be divided and still be the same substance