Atoms, Elements and Compounds
400 questions· page 1 of 40
Sodium is added to water and a chemical reaction occurs. Hydrogen and aqueous sodium hydroxide are produced.
Which row describes the reactants and products in this reaction?
Options
| reactants and products that are elements | reactants and products that are compounds | reactants and products that are mixtures | |
|---|---|---|---|
| A | hydrogen | water and sodium | aqueous sodium hydroxide |
| B | hydrogen and sodium | water | aqueous sodium hydroxide |
| C | aqueous sodium hydroxide | hydrogen and sodium | water |
| D | sodium and water | aqueous sodium hydroxide | hydrogen |
An atom of element X is shown.
Which element is X?
Options
A beryllium
B boron
C carbon
D magnesium
Which definition of isotopes is correct?
Options
A atoms of different elements that have the same number of electrons
B atoms of different elements that have the same number of neutrons
C atoms of the same element that have different numbers of electrons
D atoms of the same element that have different numbers of neutrons
A pure sample of element X has a relative atomic mass of 51.8.
The sample consists of three isotopes.
The table shows the relative masses and percentage abundances of two of the isotopes.
| relative mass of isotope | percentage abundance of isotope |
|---|---|
| 50 | 40 |
| 55 | 20 |
What is the relative mass of the third isotope?
Options
A 51
B 52
C 53
D 54
Magnesium reacts with oxygen to form magnesium oxide.
Which row is correct?
Options
| structure of | structure of | |||
|---|---|---|---|---|
| A | giant lattice | simple molecules | anion | cation |
| B | simple molecules | giant lattice | anion | cation |
| C | giant lattice | simple molecules | cation | anion |
| D | simple molecules | giant lattice | cation | anion |
Which statement about solid calcium chloride is correct?
Options
A It conducts electricity.
B It has a low melting point.
C It has an ionic lattice structure.
D It is insoluble in water.
Which description of metallic bonding is correct?
Options
A the electrostatic attraction between negative ions in a lattice and a ‘sea’ of electrons
B the electrostatic attraction between negative ions in a lattice and a ‘sea’ of protons
C the electrostatic attraction between positive ions and negative ions in a lattice
D the electrostatic attraction between positive ions in a lattice and a ‘sea’ of electrons
Element X is in Period 2 of the Periodic Table. X reacts with magnesium to form an ionic compound with the formula .
What is X?
Options
A chlorine
B fluorine
C oxygen
D sulfur
Which statement is correct?
Options
A All compounds are ionic.
B All compounds conduct electricity when molten.
C Each atom of an element contains the same number of protons.
D In a mixture of substances, the proportions of the substances are always the same.
Atoms of element Q form positive ions.
An ion of Q has 10 electrons and 14 neutrons.
Which statement is correct?
Options
A An atom of Q has only two occupied electron shells.
B Q is a non-metal.
C The atomic number of Q is 10.
D The mass number of Q is greater than 24.