science C1

Question 1

what is an element.
(broken,other,every,own type, atom)

Answer 1

a substance that cannot be broken down into any other substance, every element is made up of its own type of atom.

Question 2

how are elements arranged in the periodic table(increasing,rows,columns,100)

Answer 2

1. the chemical elements are arranged in order of increasing atomic number
2. the horizontal rows are called periods and the vertical columns are called groups.
3. there are 100 different elements.

Question 3

what is a compound and how are they represented

(pure,bonded, fomula,comprising symbols of …)

Answer 3

1. A pure substance made from more than one type of element chemically bonded together
2. using a formula, comprising symbols of elements. Eg; Water (H2O)

Question 4

what is the basic structure of an atom(nucleus,containing, surrounded, shells, number of subatoomic particles, calculated from)

Answer 4

a nucleus containing protons and neutrons, surrounded by electrons in shells. The number of subatomic particles in an atom can be calculated from the atom’s atomic number and mass number.

Question 5

explain why mass is conserved in a chemical reaction(atoms, reactants, apart, rearrange, re bond, different arrangement, form, new, left, conserved)

Answer 5

The atoms from the reactants come apart, rearrange and re-bond in a different arrangement to form the products. No new atoms have entered or left the system so the mass is conserved.

Question 6

explain the difference between a compound and a mixture(molecules, two,chemically,atoms,combination,compounds,physically rather than)

Answer 6

a compound is made up of molecules which are made of two or more different types of chemically bound atoms.

But the mixture is a combination of two or more elements or compounds that are combined physically rather than chemically.

Question 7

describe the process of fractional distillation(mixture,several,such as,crude, is, eva… components are, C as they condense, temperatures, used to seperate different, mixture)

Answer 7

a mixture of several substances, such as crude oil, is distilled and the evaporated components are collected as they condense at different temperatures. is used to separate different liquids from a mixture of liquids.

Question 8

describe how evidence from experiments changed the model of the atom(gold foil experiment, space, dense, charged,nucleus,based on these results, proposed,nuclear)

Answer 8

Rutherford’s gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus. Based on these results, Rutherford proposed the nuclear model of the atom.

Question 9

describe isotopes using the atomic model(members of, same number of, different number of,number of,determines,atomic number,on)

Answer 9

members of a family of an element that all have the same number of protons but different numbers of neutrons. The number of protons in a nucleus determines the element’s atomic number on the Periodic Table.

Question 10

explain why elements in the same group reacts in a similar way(in each group,number,valence, as a result, often display, properties and reactivity)

Answer 10

The elements in each group have the same number of valence electrons. As a result, elements in the same group often display similar properties and reactivity.

Question 11

list the four separation techniques( F , D , CR , CH )

Answer 11

filtration, distillation, crystallisation and chromatography.

Question 12

what are the key parts of the plum pudding model of the atom(negatively, embedded, uniform, positively, soup)

Answer 12

negatively-charged electrons embedded within a uniform sphere of positively-charged “soup”

Question 13

what were the key parts of the nuclear model of the atom(consist, central, dense, positively, surrounded, negatively)

Answer 13

atoms consist of a tiny central nucleus that is dense, indivisible and strongly positively charged. The nucleus is surrounded by negatively charged electrons.

Question 14

what is an isotpe(forms of, same number, P, diffrent number, N)

Answer 14

forms of an element that have the same number of protons but different numbers of neutrons

Question 15

what is the max number of electrons in the first energy levels

Answer 15

• 1st energy level/shell max number of electrons is 2
• 2nd energy level/shell max number of electrons is 8
• 3rd energy level/shell max number of electrons is 8

Question 16

what are the charge of atoms(every, overall, contain, positive protons, negative E, cancel, making, atom)

Answer 16

Every atom has no overall charge (neutral). This is because they contain equal numbers of positive protons and negative electrons. These opposite charges cancel each other out making the atom neutral.

Question 17

what is a mixture(substance, compounds, or both, consists of, not, together)

Answer 17

a substance that can be elements, compounds, or both. consists of two or more different substances, not chemically joined together.

Question 18

what is an ion(electrically charged, or group of, formed, of electrons)

Answer 18

electrically charged atom or group of atoms formed by the loss or gain of electrons.

Question 19

when would fractional distillation be used(separating, liquids from, homogeneous)

Answer 19

separating more than two types of liquids from a homogeneous mixture

Question 20

list the 4 major significant models for the atom(dalton,ball,concept,electrons,unkown,1808 – j.j,made up of, charged sphere, negatively charged, implanted,plum,1904 – rutherford, negatively charged, orbited, speed, paths,1911 – Neil B, fixed orbitals, between, explained, eqach orbit, F enegry, 1913)

Answer 20

• Dalton’s Model of the Atom , defined an atom to be a ball-like structure + concepts of atomic nucleus and electrons were unknown at the time, 1808
• j.j thomson’s model of atom, an atom is made up of a positively charged sphere where negatively charged electrons are implanted ( aka plum pudding model ), 1904
• Rutherford’s Atomic Model , negatively charged electrons orbited the nucleus of an atom in very high speed in circular paths, 1911
• Neil Bohr’s Atomic Theory ,electrons move in fixed orbitals (shells) and not anywhere in between and he also explained that each orbit (shell) has a fixed energy, 1913