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Ch 4 Sec1 & 2
Introduction to Atoms and the Periodic Table
Question | Answer |
---|---|
atom | The basic particle from which all elements are made. |
electron | A negatively charged particle that is found outside the nucleus of an atom. |
nucleus | The central core of the atom, containing protons and usually neutrons. |
proton | A positively charged particle that is part of an atom's nucleus. |
energy level | A region of an atom in which electrons of the same energy are likely to be found. |
neutron | A small particle in the nucleus of an atom, with no electrical charge. |
atomic number | The number of protons in the nucleus of an atom. |
isotope | An atom with the same number of protons and a different number of neutrons from other atoms of the same element. |
mass number | The sum of protons and neutrons in the nucleus of an atom. |
atomic mass | The average mass of all the isotopes of an element. |
periodic table | A chart of the elements showing the repeating pattern of their properties. |
period | A horizontal row of elements in the periodic table. |
group | Elements in the same vertical column of the periodic table; also called a family. |
chemical symbol | A one- or two-letter representation of an element. |
plasma | A gas-like state of matter consisting of a mixture of free electrons and atoms that are stripped of their electrons. |
nuclear fusion | The process in which two atomic nuclei combine to form a larger nucleus, forming a heavier element and releasing huge amounts of energy. |
Where were the electrons located in Thomson's model of an atom? | This model had electrons scattered throughout a ball of positive charge. |
Where are the electrons located in the modern model of an atom? | These are located in a cloudlike region surrounding the nucleus. |
In general, why did atomic theory change with time? | This change was because scientists obtained new experimental evidence about the structure of atoms. |
What are the three main particles in the modern model of an atom? | These are protons, electrons, and neutrons. |
Why do atoms have no electrical charge even though most of their particles have charges? | Each atom has equal numbers of positively charged protons and negatively charged electrons. |
What is atomic number, and how is it used to distinguish one element from another? | The number of protons in each atom of that element; each element has a unique atomic number because all atoms of that element have the same number of protons. |
The atomic number of the isotope nitrogen-15 is 7. How many protons, neutrons, and electrons make up an atom of nitrogen-15? | Each atom of nitrogen-15 contains 7 protons, 8 neutrons, and 7 electrons. |
What properties do silver and copper share? | Silver and copper are both shiny metals that tarnish in air. |
Why is the atomic mass of an element an average? | Because most elements consist of a mixture of isotopes. |
Where are elements heavier than iron produced? | These are produced in a supernova. |
List three kinds of information about an element that can be found in a square of the periodic table. | Element's name, chemical symbol, atomic number, and atomic mass. |
What element has 47 protons in its nucleus? | How many protons does silver have in its nucleus? |