Flashcards
ELEMENTS
Flashcards do conjunto (22)
- 1ELEMENTSUnit 6.1
- 2ATOMSEvery substance in the universe is made up of building blocks known as atoms. There are about 100 types of atoms.
- 3STMAtoms are so small that they cannot be seen with even the most powerful optical microscope. Instead scientists must use a scanning tunnelling microscope (STM).
- 4ELEMENTSElements are substances that are made up of just 1 type of atom. e.g. copper, oxygen, iron, hydrogen and gold. There are 118 known elements but only 98 of these occur naturally-the rest must be made in a laboratory.
- 5PROPERTIESEach element has a unique set of characteristics that scientists refer to as its properties. These properties determine whether an element is classified as metallic or non-metallic. They also determine how the elements can be used.
- 6METALLIC ELEMENTSAluminium, iron, mercury, gold and silver are all examples of metallic elements. Metallic elements all share some characteristic properties.
- 7METALS:1. Tend to be shiny or can be polished to make them shiny. This is referred to as being lustrous.
2. Are solid at room temperature.
3. Are good conductors of heat and electricity.
4. Can be bent and hammered into sheets. This is referred to as being malleable.
5. Can be stretched into wires. This is referred to as being ductile. - 8NON-METALLIC ELEMENTSNon-metallic elements have lower melting and boiling points than metals and tend to be solids or gases at room temperature.
- 9NON-METALS:1. Tend to be dull (not shiny).
2. Do not conduct heat or electricity. Non-metals are insulators for electricity and heat.
3. Break or crumble when you bend them. Non-metals are referred to as being brittle. - 10PERIODIC TABLE
- 11CHEMICAL SYMBOLSEach element has a name and a chemical symbol. Often the chemical symbol of an element comes directly from its name. For example the element calcium is given the symbol Ca.
- 12ATOMS IN ELEMENTSElements are made up of just one type of atom. However, the atoms in elements can be arranged in different ways. The atoms can exist:
1. As single atoms.
2. In clusters of atoms called molecules.
3. In large grid-like structures called lattices. - 13MONATOMIC ELEMENTSAn element that is made up of many individual atoms is known as monatomic. Monatomic elements are rare, with only six of the 98 naturally occurring elements being monatomic. These are helium, neon, krypton, argon, xenon and radon.
- 14MOLECULESClusters of two or more atoms bonded (joined) together.
- 15MOLECULAR ELEMENTSMost non-metallic elements are made up of molecules. In a molecular element, all the molecules are identical, with the same size, shape, number and type of atoms.
- 16CRYSTAL LATTICESCrystal lattices are grid-like structure that repeat the same arrangement of atoms over and over. All metallic elements form crystal lattices. Only a few non-metallic elements form lattices.
- 17METALLIC LATTICES80% of elements are metals. The atoms in metals form lattices, rather than molecules. The lattice structure makes metals dense, strong and solid at room temperature.
- 18NON-METTALIC LATTICESOnly a few non-metallic elements form lattices. An example is silicon.
- 19CARBONCarbon is an incredibly useful element as it can be found in many different forms. Different forms of the same elements are called allotropes.
- 20CHARCOALCarbon in the form of charcoal is used for sketching because it is black and soft and crumbles easily. It is also used for the process of smelting iron.
- 21GRAPHITEGraphite is a dark grey and brittle form of carbon that is commonly found in lead pencils.
- 22DIAMONDDiamond is another form of carbon. In diamond, all the carbon atoms are tightly bonded (joined) together in a rigid crystal lattice.
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- FlashCards sobre ELEMENTS, criado por Hajer JEHEL em 16-05-2017.
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