Elements and Compounds

Question 1

alkali metal

Answer 1

A soft, shiny metal that is highly reactive and located in the first group of the periodic table

Question 2

atom

Answer 2

The smallest particle of an element, made up of even smaller ‘subatomic’ particles

Question 3

atomic number

Answer 3

The number by which elements are ordered in the periodic table, e.g., carbon has the atomic number 6

Question 4

boiling point

Answer 4

The temperature at which a substance changes from liquid to gas, e.g., rhenium has the highest known boiling point at 5590°C

Question 5

brittle

Answer 5

Easily broken, characteristic of many non-metal elements

Question 6

chemical bond

Answer 6

An attractive force that holds two atoms together, broken or formed during chemical reactions

Question 7

chemical formula

Answer 7

A symbol showing the chemical composition of a substance, e.g., the formula for water indicates 2 hydrogen atoms for each oxygen atom

Question 8

chemical reaction

Answer 8

The re-arrangement of atoms to form one or more new substances, e.g., hydrogen and oxygen gases react to form water

Question 9

chemical symbol

Answer 9

One or two letters used to represent an element, e.g., Au for gold

Question 10

compound

Answer 10

A substance made up of two or more types of atom bonded together, e.g., water is made of one oxygen atom bonded to two hydrogen atoms

Question 11

element

Answer 11

A substance made up of only one type of atom, e.g., gold is an element made up of only gold atoms

Question 12

group

Answer 12

A column in the periodic table, where elements have similar properties and atomic number increases from top to bottom

Question 13

lattice

Answer 13

A repeating arrangement of atoms in a solid, forming highly ordered structures held together by bonds between atoms

Question 14

malleable

Answer 14

Able to be hammered or pressed into shape without breaking, characteristic of most metals

Question 15

melting point

Answer 15

The temperature at which a substance changes from solid to liquid, generally higher for metals than non-metals

Question 16

metal

Answer 16

A shiny element that conducts heat and electricity, occupying the entire periodic table except the top right corner

Question 17

mixture

Answer 17

A combination of substances that can be physically separated, with mixed substances not chemically combined

Question 18

molecule

Answer 18

A group of atoms bonded together, e.g., an oxygen gas molecule is made up of two oxygen atoms bonded together

Question 19

noble gas

Answer 19

An element that is highly non-reactive, located in the last group of the periodic table

Question 20

non-metal

Answer 20

An element that typically does not conduct heat or electricity, located in the top right corner of the periodic table

Question 21

non-reactive

Answer 21

Tending not to chemically interact with other substances, e.g., helium is non-reactive

Question 22

period

Answer 22

A row in the periodic table, where elements have different properties and atomic number increases from left to right

Question 23

periodic table

Answer 23

A grid arrangement of all known chemical elements, developed by Dmitri Mendeleev in the 1860s

Question 24

pure substance

Answer 24

A single substance without anything mixed in, including elements and compounds

Question 25

reactive

Answer 25

Tending to chemically interact with other substances, leading to chemical reactions when mixed together