Science 8th Grade--Chapter 4-Review 4.1

The atomic number of the isotope nitrogen-15 is 7. How many protons, neutrons and electrons make up an atom of nitrogen-15?

7 protons, then 7 electrons......therefore, 8 neutrons......7 + 8 = 15 atomic number

Why do atoms have no electric charge even though most of their particles have charges

each atom has an equal number of positively charged protons and negatively charged electrons. cancels the charges out

what is atomic number and how is it used to distinguish one element from another element

indicates the number of protons in each atom. each element has a unique number. all atoms of that elements have the same number of protons

What are the three main particles of an atom?

protons, neutrons, electrons

In general, why did atomic theory change with time?

scientists did experiments and gained new information about the structure of the atoms

What specific information did Bohr contribute to scientists understanding of the atom?

that electrons had specific amounts of energy and this gave information to the idea about energy levels of an atom

Describe Bohr's model of the atom

this model consisted of a central nucleus surrounded by electrons in specific orbits. Also, this model said that electrons could have only specific amounts of energy

How is the modern atomic model different from Bohr's atomic model?

this model stated that the atom had a small nucleus containing both protons and electrons and that the nucleus is surrounded by a cloudlike region of electrons of specific energy levels