Year 10 Chemistry Flashcards
Atomic Mass meaning
Weight of the atom. It is derived at by adding the number of protons with the number of neutrons.
How are elements organized in the periodic table.
In rows and groups according to increasing atomic number
What is an isotope
An atom with the same number of protons but different numbers of neutrons. (more or less neutrons than protons.)
What are alkali metals
Highly reactive elements, group 1. Have 1 valence electron which they will readily lose to form cations with a charge of +1. Lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) and francium (Fr) are the alkali metals. Alkali metals will react to produce similar compounds (all react to chlorine to form ionic compound.) Very soft most can be cut with a knife. React violently with water producing hydrogen gas and a metal hydroxide (an alkali). To avoid unwanted reactions store completely submerged in oil. Excellent conductors of heat and electricity. Never found in their pure form in nature due to their high reactivity but are instead found as compounds.
Reactivity of Groups
The reactivity of groups increases as you move down the group because the valence electrons are getting further from the nucleus, and are easier to remove.
What are ions
An atom or molecule that has gained or lost one or more of its valence electrons, giving it a net positive or negative electrical charge.
What are alkali earth metals
All alkaline earth metals are reactive, though not as reactive as alkali metals. Due to having 2 valence electrons, ions with a charge of +2 are formed. Like alkali earth metals react to produce similar compounds (all react with chlorine to form ionic compounds). Beryllium (Be), magnesium (Mg), calcium (Ca), Strontium (Sr), barium (Ba) and radium (Ra) are the alkali earth metals.
What are valence electrons
The electrons found orbiting the nucleus in the outmost shell.
Similarities and Differences in alkali vs alkaline earth metals
Both are reactive metals and form similar compounds. Although, alkaline earth metals are less reactive than alkali metals due to the difference in valence electrons. However, once they react, they produce different ion changes. Alkali metals produce +1 ion charge while alkaline earth metals produce a +2 ion charge. Alkali metals have 1 valence electron which they need to lose to achieve stability (a full outer shell), where as alkaline earth metals have 2 valence electrons. It is much harder to lose 2 electrons than it is to lose 1.
The Halogens
The halogens are group 17 and consist of fluorine (F), chlorine (Cl), bromine (Br), iodine (I) and astatine (At). They are non-metals and are quite reactive. They have 7 valence electrons, so they only need 1 electron to fulfil the octet rule. They have electro gravity to easily gain this electron. The halogens reactivity decreases as we move down the rows in the group, because the electro gravity decreases as the outer shell gets further away. All halogens form similar compounds when reacting to the same element. They are typically colored and toxic. The halogens all bond covalently to form diatomic molecules. This means two of the same atoms share electrons.
Why are halogens toxic
They are toxic because they can react with most of the chemical compounds in your body. This is also why the most reactive halogens are the most toxic.
Covalently/ ionically/ covalent
C- a single covalent bond by sharing one electron.
I- an ion with a charge of one by taking one electron.
CV- atoms share valence electrons to get a complete outer shell.
The Noble Gases
They are group 18 and consist of helium (He), neon (N), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn). They are noble gases because they already have a full outer shell, so they do not have to react to fulfil the octet rule. They occur naturally in the atmosphere (except for radon) and are colorless. They are very stable and have different densities.
Subatomic
Subatomic particles consist of protons, neutrons and electrons. Subatomic means smaller than an atom.
Protons, neutrons and electrons.
Protons and neutrons compromise the nucleus, which is at the center of an atom. Protons and electrons have exactly opposite charges to each other. Opposite charges attract, which is how the electrons are held in their shells outside the nucleus. Neutrons have no charge so they keep the nucleus stable by preventing the positively charged protons from repelling each other.
Energy Shells
1st- closest to the nucleus, lower energy
2nd- further away from the nucleus, higher energy
Periodic table organisation
The period (horizontal row) an element is on the periodic table represents the number of electron shells the element has. The groups (columns) represent an element having the same number of electrons in their outer shells. The periodic table organizes the elements based on their atomic number, electron configuration and shared chemical properties. The number of protons in the nucleus of an atom defines the type of element that it is. The number of protons an atom has is called the atomic number. The bigger number next to the element in its mass number, representing the number of protons and neutrons combined.
Conservation of Mass
States that matter cannot be created or destroyed in a chemical reaction.
Decomposition
When a compound breaks down into smaller compounds or elements. These reactions occur when a single reactant breaks apart to form multiple products. Can have more than 2 products, always need 1 reactant. Digestion. AB = A + B
Synthesis/ combination
Occur when multiple reactants combine to form a single product. Can have more than 2 reactants, always need 1 product. Making materials. A + B =AB
Single displacelment
A form of substitution reaction. If a compound has 2 parts a single displacement reaction is when one of those parts is swapped for a new part. Rusting. A +BC = AC + B
Double Displacement
Another type of substitution reaction. A 2 part compound reacts with another 2 part compound. Both compounds break apart and then rearrange in a different order. Wastewater treatment. AB + CD = AD + CB
Combustion
Involve the burning of hydrocarbons (compounds containing carbon and hydrogen). CxHy + OO = OCO + HOH. (can vary)
