Periodic Table

Exercises:
Exercise 1: Choose the correct form of the verb, singular or plural.
1. Physics was / were my best subject in school.
2. Can I borrow your scissors? Mine isn’t / aren’t sharp enough.
3. Do you think the people is / are happy with the government?
4. Gymnastics is / are my favourite sport.
5. The trousers you bought for me doesn’t / don’t fit me.

Exercise 2: What is the meaning of the following expressions:
Chemical bonds, bond together, dense, density, funnel
filter paper, mixture, residue, glass rod, filtrate
Exercise 3: Here are some rules about using countable and uncountable words. Write C, if they are true for countable and U for uncountable words.

______ are also called mass nouns
______ can be both singular and plural.
______ have only one form e.g. rice.
______ can be used alone – without articles.
______ must be used with articles – a/ an or the.
______ are used with much and little
______ are used with many and few

Periodic Table

The periodic table, also known as the periodic table of elements, is a tabular display of the chemical elements, which are arranged by atomic number, electron configuration, and recurring chemical properties. The seven rows of the table, called periods, generally have metals on the left and non-metals on the right. The columns, called groups, contain elements with similar chemical behaviours. Six groups have accepted names as well as assigned numbers: for example, group 17 elements are the halogens; and group 18 are the noble gases. Also displayed are four simple rectangular areas or blocks associated with the filling of different atomic orbitals.
Some important parts in periodic table:
alkali metals, The alkaline earth metals, The noble gases
The alkali metals are a group in the periodic table consisting of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). This group lies in the s-block of the periodic table of elements as all alkali metals have their outermost electron in an s-orbital.
The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). The elements have very similar properties: they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure. The alkaline earth metals are all silver-coloured and soft, and have relatively low densities, melting points, and boiling points. All the alkaline earth metals have two electrons in their external shell, so the preferred state is to lose two electrons to form doubly charged positive ions.
The noble gases are the chemical elements in group 18 of the periodic table. They are the most stable due to having the maximum number of valence electrons their outer shell can hold. Therefore, they rarely react with other elements since they are already stable.
Put the following expressions into correct places in the Periodic Table on the next page. Then read the text about the Periodic Table and use the same expressions to fill the gaps.
symbol, atomic weight, name, atomic number, group, row, alkali metals, halogens, noble gases, lanthanides, actinides, alkaline earth metals
The most convenient presentation of the chemical elements is in the periodic table of the chemical elements, which groups elements by ___________ ___________. Due to its ingenious arrangement, columns, or _____________, and ______________, or periods, of elements in the table either share several chemical properties, or follow a certain trend in characteristics such as atomic radius, electronegativity, electron affinity, etc. The main value of the periodic table is the ability to predict the chemical properties of an element based on its location on the table. The properties vary differently when moving vertically
along the _________ of the table, than when moving horizontally along the ______________. The periodic table was first devised in 1869 by the Russian chemist Dmitri Mendeleev. Mendeleev intended the table to illustrate recurring ("periodic") trends in the properties of the elements. The layout of the table has been refined and extended over time, as new elements have been discovered, and new theoretical models have been developed to explain chemical behaviour.
Various layouts are possible to emphasize different aspects of behaviour; the most common forms, however, are still quite similar to Mendeleev s original design.