8th Grade: Periodic Table

What are two reasons why diagrams of atoms not drawn to scale?

1. Electrons are much smaller than protons and neutrons. 2. The nucleus is much smaller than the overall atomic size. The nucleus is dense as it's concentrated in a small volume. However, the whole atom has 10000 times the volume of the nucleus.

What's the electron configuration for C?

2, 4

What's the electron configuration for Na?

2, 8, 1

What's the electron configuration for P?

2, 8, 5

What's the electron configuration for Ca?

2, 8, 8

What are the main differences of metals and non metals? Explain each. (6)

Appearance: metals are typically lustrous and shiny. Melting points: non metals > low; gases or liquids at room temperature (e.g carbon or hydrogen) Density: metals > high density since most are solids. Conductivity: non metals are poor conductors, mostly act as insulators. Malleability: metals > can be bent, dented, usually hammered. non metals > brittle. Ductility: metals > can be stretched in wires.

What does a group on the periodic table express?

Groups (vertical) displays the number of electrons in the outer most shell.

In terms of atomic mass, why is hydrogen unique?

Hydrogen has no neutrons.

Write a word equation for the reaction between Lithium and water.

Lithium + Water > Lithium hydroxide + hydrogen

Which holds its outer electron more strongly, a lithium or sodium atom? Explain why this is the case.

Lithium, because the negatively charged electrons are closer to the positively charged protons in the nucleus, so the attractive forces are stronger. This makes sodium more reactive than lithium.

The resulting solution affects litmus. What happens and why?

Litmus turns dark blue/purple, as the solution in alkaline. All metal oxides and hydroxides are alkaline, but these are the strongest.

Where are metals and non metals found?

Metals: on the left Non-metals: on the right

Which is more likely to be reactive, oxygen or krypton?

Oxygen is more likely to be reactive as the element needs to gain 2 electrons to get a full outer shell. In comparison, krypton has a full outer shell and does not need to gain more elements.

What does a period on the periodic table express?

Periods (horizontal) show the number of electron shells of a element.

What are the three types of subatomic particles?

Protons, neutrons and electrons.

Name the subatomic particles and their symbol, charge, relative mass (amu) and location.

Protons: P, +1, 1 and within the nucleus Electrons: E, -1, 1/2000 and orbiting the nucleus. Neutrons: N, 0, 1, and within the nucleus

What are electron shells? (3)

Shells that envelope electrons. Orbit the nucleus at fixed distances. The 2,8,8 rule (maximum amount of electrons) can be used for the first 20 elements.

What is the name for Group I elements? List them.

The Alkali metals. Hydrogen (H), Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), Francium (Fr)

On a element on the periodic table, how can you tell which is the atomic number and which is the atomic mass?

The atomic mass is a decimal (because of the electron) and the atomic number is less than the atomic mass.

What is the atomic mass?

The atomic mass is the complete mass of the atom. Each proton and neutron is 1 a.m.u. In this case, electrons are ignored for the sake of convenience.

What is the atomic number?

The atomic number is the amount of protons in the nucleus. It's considered the 'fingerprint' of an element since the number is unique to each atom.

Why is the atomic mass sometimes written as a decimal?

The influence of electrons.

Where is the mass of the atom primarily concentrated?

The nucleus. Electrons are only 1/2000 of protons and neutrons in terms of mass.

What quality of each element warrants similar reactions to other elements?

The number of electrons in their outer shell.

What's the major difference between atoms?

The number of subatomic particles.

When the Group I metal reacts, describe what happens to the outer shell of electrons.

The single electron in the outer shell is lost as the element combines with the water. The next shell inwards is now a full shell and the atom is stable.

The Group I metals all have similar chemical properties. Why is this?

They all have one electron in their outer shell.

Where are metalloids found?

They make a diagonal on the right side of the periodic table, splitting the metals and non metals.

What are some trends of Group I elements?

They tarnish easily, are stored and oil, and are easy to cut into. As we descend the metals become more reactive.

What's the overall charge of the atom?

Zero, as there are the same amount but opposite charge of protons and electrons.

what is the trend of reactivity and softness in the group I elements?

as you descend, the elements gradually become softer and more reactive. following this rule: lithium is the hardest, and least reactive. francium is the softest, and the most reactive.

why do the group I metals gradually get more reactive?

as you move down the period the nucleus gains more neutrons and protons. the electrons are further away from the nucleus, which makes the electrostatic force holding them together weaker. this makes the electron easier to lose, hence more reactive.

What are three common metals in use around us?

e.g gold, aluminum, iron, sodium

Two non metals that we breathe in

e.g. oxygen, nitrogen, argon

what is the name for group VII elements? list them

halogens. fluorine (F), chlorine (Cl) bromine (Br), iodine (I), and astatine (At). fluorine is most reactive.

what are some trends of the group VII elements?

have 7 electrons in their outer shell. bond readily with other substances, making them most active non-metals. never found free in nature, react with alkali metals easily, forming salts.

what are the rare earth elements, and their trends?

lanthanides and actinides. the block of metallic elements that sit below the main elements. many are man made and radioactive. uranium is used as fuel for nuclear reactors.

what is the name for the group VIII elements? list them.

noble gases. helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).

what happens to the solubility, acidity, strength and how volatile the group VII elements are as you descend? explain.

solubility, acidity, strength of the halogens decrease. the halogens become less volatile. this is because the atoms in the halogens become larger. astatine would be solid at room temperature and least reactive.

how are elements classified through reaction with oxygen?

some metals and non metals can be classified on whether they are soluble (alkaline) or insoluble (acidic) in oxygen. their characteristic colors can also be used.

what happens to the density, melting and boiling points for group I elements as you descend?

the density increase. melting and boiling points decrease > volatile.

what is pH?

the universal indicators to see how acidic (pH 1) or alkaline (pH 14) the oxide is. the scale is numbered from 1 to 14, and a variety of colors. a solution that is neutral (pH 7) is strong green, while an alkaline oxide is purple or dark blue.

what are transition metals? list examples and trends.

they are the central block of elements between groups II and III. consists of iron, silver, tin, copper, zinc and the like. typically good conductors of heat and electricity, have 1 or 2 electrons in outer shell.

why are group VII elements so unreactive?

they have full electron shells.

how do the group I metals react to hydrogen?

very strongly. they float and burn on the surface with characteristic flame colors, the remaining solution containing hydroxide which is highly alkaline (pH 13/14)