Chlorine naturally has 17 electrons but it would be more stable with 18 electrons 2 in its inner most shell, 8 in its second shell, and 8 in its valence shell.
Therefore, chlorine will take an electron from another atom to become negatively charged. Periodic Properties: Part 3, Ionic Radius, Predicting Ionic Charges — YouTube : A continuation of the discussion of periodic properties, including ionic radius and how to predict ionic charges. Privacy Policy. Skip to main content.
Atoms, Molecules, and Ions. Search for:. The Periodic Table The Periodic Table The periodic table shows all the elements and their physical properties; it is arranged based on atomic numbers and electron configurations. Learning Objectives Identify the common periodic trends that can be deduced from the periodic table of elements. Key Takeaways Key Points The periodic table lists all the elements, with information about their atomic weights, chemical symbols, and atomic numbers. The arrangement of the periodic table leads us to visualize certain trends among the atoms.
The vertical columns groups of the periodic table are arranged such that all its elements have the same number of valence electrons. All elements within a certain group thus share similar properties. Key Terms atomic number : The number, equal to the number of protons in an atom, that determines its chemical properties.
Molecules Molecules are electrically neutral compounds made of multiple atoms bound together by chemical bonds. Learning Objectives Recognize the general properties of molecules. Key Takeaways Key Points Molecules are neutral and do not carry any charge. A molecule may consist of nonmetallic atoms of a single chemical element, as with oxygen O 2 , or of different elements, as with water H 2 O.
The geometry and composition of a molecule will determine its chemical and physical properties. Key Terms covalent : when 2 or more nonmetallic atoms are bound together by sharing electrons. All compounds are molecules but not all molecules are compounds.
Ions An ion is an atom or molecule that has a net electrical charge because its total number of electrons is not equal to its number of protons. Protons decide which element an atom is, while outermost electrons call the shots on how the atom behaves chemically. And between them, they determine which elements can conduct heat and electricity, which are gases, and which are capable of being the basis of life.
And you can tell all of that and more just by knowing where an element sits on the periodic table. It's not exactly the Da Vinci code, but there's an underlying message in the rows and columns of the table. If you don't know anything about how electrons are arranged around an atom, the pattern in the rows won't make any sense.
But if you've got even a distant memory of Year 9 chemistry and electron shells, some bells might start ringing. Electrons aren't buzzing around the nucleus of an atom like flies around manure — they exist in different energy 'shells'. Each shell can only hold a certain number of electrons, and the shells have to be filled in order from the one closest to the nucleus out. Starting from the shell closest to the nucleus, the electron shells of an atom can hold two, eight, eight, 18, 18, 32 and 32 electrons.
And in order from top to bottom, the rows of the periodic table hold two, eight, eight, 18, 18, 32 and 32 elements. So when you see the position of an element in the table, you can tell straight away how full its outermost electron shell is.
Hydrogen in row 1, column 1 has one electron in shell 1. Sodium Na, row 3, column 1 has one electron in its third shell. Magnesium Mg has two outer electrons, oxygen O has 6, and carbon C and silicon Si both have four. And in the far right column are the six known elements with a full outer shell, the noble gases.
And for atoms, a full outer shell is where it's at. Atoms with a full outer shell are chemically stable — they can sit around unchanged for the rest of eternity or at least until they get swallowed by the sun or sucked into a black hole and fused together with other atoms. But while only noble gases are 'born' that way, all the other elements can fake their way to a more stable existence.
Their atoms can share, steal or offload electrons by forming chemical bonds with other atoms so they can each end up with a full outer shell. And that's where the table's layout really comes into its own. Like a match-making guide for elements that aren't exactly noble, at a glance you can tell what goes with what, and how many times.
If an atom doesn't have 36 protons, it can't be an atom of krypton. Adding or removing protons from the nucleus of an atom creates a different element. For example, removing one proton from an atom of krypton creates an atom of bromine. By definition, atoms have no overall electrical charge. That means that there must be a balance between the positively charged protons and the negatively charged electrons. Atoms must have equal numbers of protons and electrons.
In our example, an atom of krypton must contain 36 electrons since it contains 36 protons. Electrons are arranged around atoms in a special way. If you need to know how the electrons are arranged around an atom, take a look at the ' How do I read an electron configuration table? An atom can gain or lose electrons, becoming what is known as an ion.
An ion is nothing more than an electrically charged atom. Adding or removing electrons from an atom does not change which element it is, just its net charge. The plus sign means that this is a positively charged ion. It is positively charged because a negatively charged electron was removed from the atom. No account yet? Create an account. Edit this Article. We use cookies to make wikiHow great.
By using our site, you agree to our cookie policy. Cookie Settings. Learn why people trust wikiHow. Download Article Explore this Article parts. Related Articles. Article Summary. Part 1. Get a periodic table of elements. The periodic table is a chart that organizes elements by their atomic structure. It is color-coded and assigns each element a unique 1 or 2-letter abbreviation. Other elemental information includes atomic weight and atomic number. In tests, normally, a periodic table will be provided.
Find your element on the periodic table. The table orders elements by atomic number and separates them into three main groups: metals, non-metals, and metalloids semi-metals. Further elemental groupings include alkali metals, halogens, and noble gases. The atomic number is located above the element symbol, in the upper left-hand corner of the square.
The atomic number will tell you how many protons make up a single atom of an element. Determine the number of electrons. Electrons are particles that have a negative charge equal to Therefore, an element in a neutral state will have the same number of protons and electrons. For example, boron B has an atomic number of 5, therefore it has 5 protons and 5 electrons.
However, if the element includes a negative or positive ion, then the protons and electrons will not be the same. You will have to calculate them. The ion number will appear as a small superscript after the element. Look for the atomic mass of the element. To find the number of neutrons, you will first need to find the atomic mass. Make sure that you round the atomic mass to the nearest whole number.
For example, the atomic mass of boron is Subtract the atomic number from the atomic mass.
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