NCEA Level 1 Science Acids & Bases

Base/Alkali

' Anti-Acids'. Alkalis are bases that dissolve in water, releasing Hydroxide ions. Bases & Alkalis are everyday chemicals that are slippery to touch, turn UI blue-purple, are bitter to taste and can be extremely corrosive

pH scale

A scale from 0-14 that indicates the acidity or alkalinity of a substance, with anything below 7 being acidic and anything above seven being basic/alkaline.

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

Periodic table

A table that shows the elements, their atomic number, symbol and atomic mass. Elements with similar chemical properties are grouped together

Acid

Acids release Hydrogen ions in water. They are common substances found in everyday life, they are sour to taste and change UI yellow-red.

Negative ion

An atom that most likely had either four, five or six electrons in its outer shell and gained electrons to have a full outer shell.

Positive ion

An atom that most likely had either one, two or three electrons in its outer shell, and lost them to gain a full outer shell

Ionic compound

Compounds formed from charged ions being attracted after they have completely transferred electrons from one atom to another (becoming charged).

Universal indicator

Follows the pH scale, concentrated acids will turn this indicator red, dilute acids will turn it yellow, neutral solutions will turn it green, dilute bases will turn it blue and concentrated bases turn it deep purple

Noble gasses

Group 18 elements of the periodic table. They are quiet unreactive, as they already have full outer shells, include He (helium) Ne (neon) Ar (argon)

Periods

Horizontal rows of the periodic table

Element

Pure substance made up of only one kind of atom

Nucleus

The central most part of an atom, contains positively charged particles called protons and neutral particles called neutrons

Activation energy

The minimum amount of energy required for a particular reaction to occur

Atom

The smallest known neutral particle of any chemical element

Anions

ions with a negative charge

Cations

ions with a positive charge

Electron

A subatomic particle that has a negative charge and that is found in the outer shells (orbits) of an atom. Have a mass of less than 1/1000 of a protons mass

Neutron

A subatomic particle that has a no charge (neutral) and that is found in the nucleus of an atom

Litmus

An indicator that begins as either a blue or red colour and changes to red in an acidic solution and blue in a basic solution

Neutralisation reaction

Any reaction between an acid and a base (alkalis, carbonates, oxides). These reactions will always form a salt and water

Acid and carbonate

Any reaction that forms a salt, water and carbon dioxide is between an ____ and a _________

Ions

Atoms or groups of atoms that reacted to become more stable, losing or gaining electrons to acquire a full outer shell, they gain a negative or positive charge in doing so because of differences in their numbers of protons and electrons.

Electron configuration

The arrangement of electrons in the shells of an atom. - the first shell will hold a maximum of two electrons -the second shell will hold a maximum of eight electrons -the third shell will hold a maximum of eight electrons -the fourth shell will hold a maximum of two electrons this only applys to the first 20 elements

Mass Number

The total number of protons and neutrons in the nucleus of a given atom. The number of electrons doesnt have much effect on the mass of an atom as they have a mass of less than 1/1000 of a protons mass

Atomic Number

The total number of protons in the nucleus of a given atom, will be equal to the number of electrons in the same atom

Rate of reaction

This is how fast a particular reaction occurs, and is influenced by temperature, surface area or reactants, pressure, concentration of reactants and catylists

Collision theory

This theory says that particles cannot react unless they come in contact with one another, and the reactions will not occur if there isn't enough energy in the contact, reactions also rely on the orientation of the particles

Groups

Vertical columns in the periodic table. all of the atoms in a particular group show similar characteristics