GCSE Chemistry: The Periodic Table Flashcards

Question 1

Define The Periodic Table.

Accepted Answer

A chart that arranges all known chemical elements in order of increasing atomic number, grouped so elements with similar chemical properties line up in the same vertical column.

Question 2

Define Atomic Number.

Accepted Answer

The number of protons in the nucleus of an atom, which also equals the number of electrons in a neutral atom and fixes which element it is.

Question 3

Define Mass Number.

Accepted Answer

The total number of protons and neutrons in an atom's nucleus, used to identify a specific isotope of an element rather than the element in general.

Question 4

What is Isotope?

Accepted Answer

One of two or more atoms of the same element that have the same number of protons but a different number of neutrons, giving them different mass numbers.

Question 5

What is Period?

Accepted Answer

A horizontal row of the periodic table. Moving across a period from left to right, atoms gain one proton and one extra outer-shell electron for each step, without gaining a new shell.

Question 6

What is Group?

Accepted Answer

A vertical column of the periodic table. Elements in the same group have the same number of electrons in their outer shell, giving them similar chemical properties.

Question 7

Define Electron Shell.

Accepted Answer

An energy level surrounding an atom's nucleus that can hold a fixed maximum number of electrons before the next shell out starts to fill.

Question 8

Define Electronic Configuration.

Accepted Answer

The arrangement of an atom's electrons across its shells, written as a series of numbers separated by commas starting from the innermost shell.

Question 9

Define Alkali Metals.

Accepted Answer

The elements of Group 1: soft, low-density metals with one outer electron that react vigorously with water and oxygen, so they are stored under oil to stop them oxidising.

Question 10

Define Group 1 Reactivity Trend.

Accepted Answer

The pattern that alkali metals become more reactive going down the group, because the single outer electron sits further from the nucleus and is held less tightly, so it is lost more easily.

Question 11

What is Halogens?

Accepted Answer

The elements of Group 7: non-metals that exist as pairs of atoms bonded together, and that become less reactive going down the group as the outer shell gets further from the nucleus.

Question 12

Define Group 7 Reactivity Trend.

Accepted Answer

The pattern that halogens become less reactive going down the group, because a larger atom makes it harder for the nucleus to pull one more electron into a now-distant outer shell.

Question 13

Define Halogen Displacement Reaction.

Accepted Answer

A reaction in which a more reactive halogen takes the place of a less reactive halogen inside a dissolved metal halide, providing direct evidence for the Group 7 reactivity trend.

Question 14

Define Noble Gases.

Accepted Answer

The elements of Group 0, each with a complete outer shell of electrons, which makes them extremely unreactive under normal laboratory conditions.

Question 15

Define Transition Metals.

Accepted Answer

The block of metallic elements between Group 2 and Group 3, typically dense with high melting points, forming coloured compounds and sometimes several different ion charges.

Question 16

Define Metallic Character Trend.

Accepted Answer

The tendency of elements to behave like metals, which increases moving down a group and decreases moving left to right across a period.

Question 17

Define Ionisation Energy.

Accepted Answer

The energy needed to remove one electron from an atom in the gas state, which generally falls going down a group as the outer electron sits further from the attracting nucleus.

Question 18

Define Atomic Radius Trend.

Accepted Answer

The pattern in atom size: radius increases going down a group as extra electron shells are added, and decreases going across a period as extra protons pull the same-shell electrons in tighter.

Question 19

What is Proton?

Accepted Answer

A positively charged particle found in the nucleus of an atom, whose total count sets the atomic number and therefore the element's identity.

Question 20

What is Neutron?

Accepted Answer

A particle carrying no electric charge, found in the nucleus alongside protons, that adds to an atom's mass without affecting its charge or which element it is.

Question 21

Define Relative Atomic Mass.

Accepted Answer

The average mass of an element's naturally occurring atoms, weighted by how common each isotope is, measured against one-twelfth the mass of a carbon-12 atom.

Question 22

Define Mendeleev's Periodic Table.

Accepted Answer

The 1869 arrangement by Dmitri Mendeleev that ordered elements by atomic mass and deliberately left gaps for undiscovered elements, correctly predicting their properties in advance.

Question 23

Define Newlands' Law of Octaves.

Accepted Answer

An earlier 1865 attempt by John Newlands to order elements by atomic mass, noticing similar properties repeating every eighth element, but the pattern broke down after calcium and was dismissed at the time.

Question 24

Define Metal-Nonmetal Divide.

Accepted Answer

The zigzag line running through the periodic table separating metals, on the left and centre, from non-metals, on the upper right, with metalloids sitting close to the line.

Question 25

Define Valence Electron.

Accepted Answer

An electron in an atom's outermost occupied shell, the electrons directly involved in forming chemical bonds and in determining how reactive an element is.

Question 26

Define Period 3 Elements.

Accepted Answer

The eight elements from sodium to argon, which shift from reactive metal, through reactive non-metal, to unreactive gas as atomic number increases across the row.

Question 27

Define Uses of Noble Gases.

Accepted Answer

Practical applications of Group 0 elements that rely on their lack of reactivity, including filling light bulbs and providing an unreactive atmosphere for welding.

Question 28

Define Chemical Symbol.

Accepted Answer

A one- or two-letter abbreviation representing an element, with the first letter always capitalised and any second letter always written in lower case.

Question 29

Define Group 1 + Water Reaction.

Accepted Answer

The reaction of an alkali metal with water, producing a dissolved metal hydroxide and hydrogen gas, often seen as fizzing, movement across the surface, or a lilac or orange flame.

Question 30

Define Diatomic Molecule.

Accepted Answer

A molecule made of exactly two atoms bonded together, the natural form taken by each of the halogens at room temperature and pressure.