chapter 4 chemistry test 1. Why do Li, Na, K, Rb, Cs, and Fr all react with Cl in a 1:1 ratio forming sub

In general, the_____________________ are metals that are less reactive than the alkali metals and the alkaline earth metals. they .

transition metals

7. Explain the importance of valence electrons.

valence electrons are important because they control how reactive the element is

10. How is the electron configuration similar for each element in a period?

The electron configuration is similar because the same number of energy levels are filled.

The_____________________ have a single electron in the highest occupied energy level.

alkali metals

The_______________________ are metals that lose one electron when they react with water to form alkaline solutions.

alkali metals

All the______________________ have two valence electrons and get to a . stable electron configuration by losing two electrons.

alkaline earth metals

why a helium atmosphere is used in welding instead of an oxygen rich atmosphere.

because it's a noble gas and is more stable

1. Why do Li, Na, K, Rb, Cs, and Fr all react with Cl in a 1:1 ratio forming substances with similar properties

because they are all alkali metals and only have one valence electron and the Cl is a halogen which has 7 so if you give the 1 valence electron to the halogen they both become noble gases making them have similar properties

What method did Dmitri Mendeleev use to arrange his periodic table?

created the first periodic table by mass and property

8. Why do elements with similar properties appear at regular intervals in the periodic table?

elements with similar properties appear at regular intervals because there are put into groups

the____________ are highly reactive and readily form salts with

halogen

The___________________________ the most reactive group of non-metals, achieve stable electron configurations by gaining one electron.

halogens

2. Explain the method that John Newlands used to organize the elements.

he arranged the elements in order of increasing atomic mass

4. Why did Mendeleev have gaps in his table? How did he use these gaps?

he had gaps because he predicted that there were elements that were not found yet and used them to predict the properties of the unknown element

5. What was Henry Moseley's contribution to the periodic table?

he thought that the periodic table should be arranged by atomic number

With its one valence electron, _______ reacts with many other elements.

hydrogen

The___________________________ are in the s- and p-blocks of the periodic table.

main group elements

most elements are ________

metals

6. Why was. Moseley able to resolve the discrepancies in Mendeleev's table when Mendeleev could not?

moseley could because he did it by atomic number which never changes and mendeleev's messed up all the time because the element property would change

The_______________________ are very stable and have low reactivity.

noble gases

the______________have a full set of electrons in their outermost energy level

noble gases

9. How is the electron configuration similar for each element in a group?

they have the same number of valence electrons

4. Unlike the main-group elements, each group of the_____________________ does not have the identical outer electron configuration.

transition metals