summary of the chapter elements, compound and mixtures
Answers
Elements
What are elements?
- elements are the building blocks of structures
- they are the smallest particles that cannot be further broken down into simpler substances via chemical process
-they are made up of either atoms or molecules
-consist of chemical bonds
Some examples of elements would include oxygen,carbon and hydrogen.
Elements are classified into three main categories: Metals, Metalloids and Non-Metals.
METALS:
-have high boiling and melting points
-are malleable, ductile and sonorous
-are lustrous
-are good conductors of heat and electricity
-usually in the solid state (except mercury)
-examples: iron,steel
METALLOIDS:
-high boiling and melting points
-are usually brittle
-lustrous
-moderate conductors of heat and electricity
-usually in the solid state
-example: silicon
NON-METALS:
-low boiling and melting points
-dull
-brittle
-poor conductors of electricity (exceptions: carbon and graphite)
-can be in solid, liquid or gaseous state
-examples: oxygen, carbon bromine
#RealLifeScenario: Let's take SUGAR as an example. When sugar is heated (heating, by the way, is a chemical process) it melts into a delicious, gooey substance called caramel. However, when heated for too long, it breaks down into CARBON and WATER VAPOUR. In this scenario, CARBON (c) is an ELEMENT. It cannot be further broken down. So that makes water vapour an element too, right? WRONG! Water vapour can be further broken down into hydrogen(h) and oxygen(o2), which are elements :) :)
Atoms vs. Molecules
Primarily, atoms are the basic units that make up elements. Molecules refer to a clump of atoms, two,three or more. Elements that are made up of only one atom are monatomic elements. Most monatomic elements are noble gases, such as argon and helium. Two chemically-combined atoms are known as diatomic molecules. Three or more chemically-combined atoms are known as polyatomic molecules.
Compounds
What are compounds?
-compounds are two or more chemically-combined elements
-compounds are made up of molecules
-compounds consist of chemical bonds
-the elements of a compound are in a fixed ratio
-the elements of a compound can only be separated via chemical processes
(example: heating/ using electricity)
-chemical reactions take place when the elements of a compound interact
and there is usually an energy change
#RealLifeExample: A very common compound is one you encounter every single day-water! The chemical representation of water is H2O. It indicates that water is made up of diatomic hydrogen(H2) molecules and an oxygen atom(o).The hydrogen molecules and oxygen atom are chemically combined.
Mixtures
-can consist of different elements, different compounds or
both elements and compounds that do not chemically react to one another
-the constituent substances in a mixture can be in any ratio
-the components can be separated via physical processes
(example: magnetic force of attraction/ properties of buoyancy)
#RealLifeExample: Most objects we see around us are mixtures. Mixtures come in two main kinds. Homogeneous mixtures consist of elements/mixtures that visibly mix with each other to form a combined whole. Most homogeneous mixtures are also called 'solutions'.
An example would include water and syrup.Heterogeneous mixtures consist of elements/compounds that do not visibly mix, such as water and oil.
Chemical Reactions: colour changes and release or intake of heat.
The Periodic Table
As most already know, all elements have their own unique chemical symbols. These symbols consist of either one (o) or two (Mg) letters. In the case of two letters, the first letter is capitalised. Single letters remain in lower case. There are 112 officially recognized elements thus far, naturally occurring and man-made. In order to aid location and research purposes, these elements are classified in the periodic table based on their various properties.
Answer:
Elements
What are elements?
- elements are the building blocks of structures
- they are the smallest particles that cannot be further broken down into simpler substances via chemical process
-they are made up of either atoms or molecules
-consist of chemical bonds
Some examples of elements would include oxygen,carbon and hydrogen.
Elements are classified into three main categories: Metals, Metalloids and Non-Metals.
METALS:
-have high boiling and melting points
-are malleable, ductile and sonorous
-are lustrous
-are good conductors of heat and electricity
-usually in the solid state (except mercury)
-examples: iron,steel
METALLOIDS:
-high boiling and melting points
-are usually brittle
-lustrous
-moderate conductors of heat and electricity
-usually in the solid state
-example: silicon
NON-METALS:
-low boiling and melting points
-dull
-brittle
-poor conductors of electricity (exceptions: carbon and graphite)
-can be in solid, liquid or gaseous state
-examples: oxygen, carbon bromine
#RealLifeScenario: Let's take SUGAR as an example. When sugar is heated (heating, by the way, is a chemical process) it melts into a delicious, gooey substance called caramel. However, when heated for too long, it breaks down into CARBON and WATER VAPOUR. In this scenario, CARBON (c) is an ELEMENT. It cannot be further broken down. So that makes water vapour an element too, right? WRONG! Water vapour can be further broken down into hydrogen(h) and oxygen(o2), which are elements :) :)
Atoms vs. Molecules
Primarily, atoms are the basic units that make up elements. Molecules refer to a clump of atoms, two,three or more. Elements that are made up of only one atom are monatomic elements. Most monatomic elements are noble gases, such as argon and helium. Two chemically-combined atoms are known as diatomic molecules. Three or more chemically-combined atoms are known as polyatomic molecules.
Compounds
What are compounds?
-compounds are two or more chemically-combined elements
-compounds are made up of molecules
-compounds consist of chemical bonds
-the elements of a compound are in a fixed ratio
-the elements of a compound can only be separated via chemical processes
(example: heating/ using electricity)
-chemical reactions take place when the elements of a compound interact
and there is usually an energy change
#RealLifeExample: A very common compound is one you encounter every single day-water! The chemical representation of water is H2O. It indicates that water is made up of diatomic hydrogen(H2) molecules and an oxygen atom(o).The hydrogen molecules and oxygen atom are chemically combined.
Mixtures
-can consist of different elements, different compounds or
both elements and compounds that do not chemically react to one another
-the constituent substances in a mixture can be in any ratio
-the components can be separated via physical processes
(example: magnetic force of attraction/ properties of buoyancy)
#RealLifeExample: Most objects we see around us are mixtures. Mixtures come in two main kinds. Homogeneous mixtures consist of elements/mixtures that visibly mix with each other to form a combined whole. Most homogeneous mixtures are also called 'solutions'.
An example would include water and syrup.Heterogeneous mixtures consist of elements/compounds that do not visibly mix, such as water and oil.
Chemical Reactions: colour changes and release or intake of heat.
The Periodic Table
As most already know, all elements have their own unique chemical symbols. These symbols consist of either one (o) or two (Mg) letters. In the case of two letters, the first letter is capitalised. Single letters remain in lower case. There are 112 officially recognized elements thus far, naturally occurring and man-made. In order to aid location and research purposes, these elements are classified in the periodic table based on their various properties.